Q&A for How to Calculate Ratios

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  • Question
    How do you calculate if something cost $175, and two people shared the cost at a ratio of 2:3?
    Community Answer
    1. You add the numbers of the ratio: 2 + 3 = 5 2. You divide the total cost ($175) by 5. 175 / 5 = 35 3. You multiply this number by each of the numbers of the ratio: 35 x 2 = 70, and 35 x 3 = 105. Solution: one paid $70, and the other one, $105. Both numbers added give you the total of 175 dollars.
  • Question
    A small theater sold 72 tickets to a play. The ratio of adults to children is 4:1. The ratio of adults to seniors is 4:3. How do I determine how much of each were sold?
    Donagan
    Top Answerer
    The ratio of adults to seniors to children is 4:3:1. Add those three numbers, and divide the sum into 72. Multiply the quotient by 4, 3, and 1 to find the number sold of each kind of ticket.
  • Question
    How do you convert the ratio 1:4 to a decimal or a percent?
    Community Answer
    You can treat a ratio as a fraction or a division problem: 1:4 = 1 / 4 = 1 ÷ 4. Solve this problem with long division (or a calculator) and you'll get the answer as a decimal: 0.25. To make this a percent, just move the decimal point two spaces to the right: 0.25 = 25%.
  • Question
    I am having trouble in working out this question: There are 600 learners in a school. The ratio from girls to boys is 3:5. How many girls are there in the school?
    Community Answer
    You can divide 600 by 8 (3 + 5 or 3:5). 600/8 = 75 x by the girl ratio of 3 = 225 and the remainder is the male total at 375.
  • Question
    I'm having trouble with this kind of problem: "In 550 mL of a mixture, the ratio of milk and water is 5:6. What is the quantity of water in the mixture?"
    Community Answer
    The ratio is saying that, if we had a (5 + 6) = 11 ml mixture of milk and water, then there would be 5 ml milk and 6 ml water. This means any mixture with this ratio is 6 / 11 water. Therefore, in a 550 ml mixture, we will have 550 x (6 / 11) = 300 ml water.
  • Question
    How do I solve this ratio: 30 girls and boys have planned for a picnic. There is a ratio of 3 girls to 7 boys. How many boys are there?
    Community Answer
    Girls + boys (3+7) = total students in groups of 10. 30/10 = 3 and there are 3 girls of that amount then you just multiply Girls 3*3 = 9 Boys 7*3 = 21.
  • Question
    How do I divide Rs. 672 in the ratio of 5:3?
    Donagan
    Top Answerer
    Add 5 + 3 = 8. Divide 8 into 672 = 84. Multiply 84 x 5 = 420, and multiply 84 x 3 = 252. 672 is then divided into a ratio of 420:252 (which is the same as 5:3).
  • Question
    I'm having trouble with this one: Jenny and Mark share some money in the ratio 2:3. Jenny's share is 110. How much is Mark's share?
    Donagan
    Top Answerer
    You have two ratios, 2:3 and 110:x, where x equals Mark's share. Express the two ratios as fractions: 2/3 and 110/x. Set the two fractions equal to each other (because the two ratios are equal to each other) and cross-multiply to solve for x. By cross-multiplying, 2x = 330, so that x = 165.
  • Question
    How do you solve this problem: Divide 33 photos into 2 groups so the ratio is 4 to 7?
    Community Answer
    The total of the two groups needs to be 33, but to obtain this the ratio needs to be constant throughout. The ratio's total starts at 11 (4+7, the total of the ratio 4:7), and in order for the grand total to be 33, you need to multiply 11 by 3 (and therefor the ratio that was added to make it). So, 11 x 3 = 33 and 4:7 x 3 is 12:21 (4 × 3 =12, 7 × 3 = 21). For verification, the ratio adds up to twenty and can still be divided to make the original ratio. 12 + 21 = 33.
  • Question
    How do you convert a decimal to a fraction?
    Community Answer
    Look at the place value of the last numeral to find the second number in the fraction. For example, 0.4 ends in the tenths place, so this means "4 / 10." The number 0.36 ends in the hundredths place, so you can write it as "36 / 100." For a number like 3.25, convert everything after the decimal point into a fraction, then convert the mixed number to an improper fraction .
  • Question
    A bouquet contains red and yellow flowers in a ratio 5:2. If there are 4 yellow flowers, how many red flowers are in the bouquet?
    Community Answer
    Multiply the ratio by 2. 5:2 x 2 = 5 x 2 (10) and 2 x 2 (4), or 10:4. 10 red flowers to 4 yellow flowers.
  • Question
    How do I start solving this problem: "There are four more girls than boys in Ms. Raub's class of 28 students. What is the ratio of number of girls to the number of boys in her class?"
    Community Answer
    You can find the answer pretty quickly by guessing and checking if the numbers work out. Or you can think of it like this: If half of the class were girls, there would be 14 girls. You can't change the total number of students, so to have more girls than boys you need to take out one boy for each girl you add. Adding two girls and taking away two boys leaves you with 16 girls and 12 boys.
  • Question
    The ratio of c:s is 1:6 and c:l is 1:10. I want to find the ratio of c:s:l. How do I go about it?
    Donagan
    Top Answerer
    Because c is expressed as a "1" in both ratios, you can use the other two numbers in the ratios to represent the other quantities. In other words, c:s:l is 1:6:10.
  • Question
    I'm having trouble with this problem: The ratio of baseballs to golf balls in a box is 2:3, and there are 30 baseballs in the box. How many golf balls are there?
    Community Answer
    If the ratio is 2:3, that means there are 2 baseballs for every 3 golf balls. This means the number of baseballs = the number of golf balls x 2/3. Rearrange the equation to get (number of baseballs) x (3/2) = (number of golf balls). 30 x 3/2 = 45, so there are 45 golf balls.
  • Question
    In the 76 games played by the excellent football team last year, the ratio of the number of games won, lost and drawn was 11:5:3. What the number of the games drawn?
    Donagan
    Top Answerer
    12. Here's how you do it: add 11 + 5 + 3 = 19. Divide 19 into 76 = 4. Multiply 4 x 3 = 12. (There were 4 x 11 = 44 wins and 4 x 5 = 20 losses.)
  • Question
    How do you find the ratio of a person that measure 6" to a person who measures 6'?
    Donagan
    Top Answerer
    That's a ratio of 1:12, because 6' is 12 times taller than 6".
  • Question
    How do you calculate this kind of problem: "The ratio of ages between Ajani and Bruna is 7:9. In 6 years the age ratio will be 4:5. What is their age now?"
    Community Answer
    Whenever you see a complicated word problem like this, try to turn it into an algebra equation. If their ages are a and b, then a = 7b/9. In six years, their ages will be a+6 and b+6, and the ratio will be (a+6) = 4(b+6)/5. Now you can follow the standard method of solving a system of equations .
  • Question
    Blue and yellow paints are mixed in a 2:5 ratio, and there are 6 more litres of yellow than blue. How do I calculate how many litres of each are mixed?
    Community Answer
    Blue : Yellow = 2:5 . 2/5 = x/(x=6). After cross multiplying we'll have 5x = 12 = 2x like terms together, 5x-2x = 12. Therefore 3x = 12 and x = 4. To answer your question, then we will have 4L of blue and 10L (4+6) of yellow.
  • Question
    If the ratio of 2x:5y is 3:4, what is the ratio of x:y?
    Donagan
    Top Answerer
    Express the given relationship as a proportion: 2x / 5y = 3/4. Cross-multiply: 8x = 15y. Divide both sides by 8y in order to arrive at x/y on one side. That's the ratio you're looking for: x / y = 15 / 8.
  • Question
    If 100 grams of flour is to 60 grams of butter, how many grams of butter is to 480 grams of flour?
    Donagan
    Top Answerer
    Set up a proportion, letting x = the number of grams of butter needed: (100 / 60) = (480 / x). Cross-multiply: 100x = (60)(480). Then x = [(60)(480)] ÷ 100 = 288 grams.
  • Question
    I need to add 2% inoculum of two cultures in the ratio of 1:5 to set curd. How much of each culture should I add to make 100 ml of curd?
    Donagan
    Top Answerer
    16 2/3 ml of one culture and 83 1/3 ml of the other.
  • Question
    How do I calculate this: Anna, Marcus and Darren shared a pie in the ratio 2:4:7; what fraction of the pie did Darren get?
    Donagan
    Top Answerer
    The ratio is presented as if there were a total of 13 pie segments (2+4+7). Darren received 7 of those segments, or 7/13 of the pie.
  • Question
    At the potluck there were six pecan pies, seven lemon pies, 13 cherry pies and eight apple pies. What is the ratio of apple pies to the total number of pies?
    Donagan
    Top Answerer
    Add all the pies. The ratio is 8 to the total number.
  • Question
    On Saturday, a library checked out 52 books. If 24 of the books were fiction, what is the ratio of nonfiction books to fiction books checked out?
    Donagan
    Top Answerer
    If 24 of the 52 books were fiction, 28 of them were non-fiction. So the ratio of non-fiction to fiction was 28 : 24. That reduces to 7:6.
  • Question
    How do I find smallest ratio between 48 to 54 pounds and 80 to 90 pounds?
    Donagan
    Top Answerer
    Those two ratios are identical, which you can demonstrate by reducing each of them as far as possible.
  • Question
    If I'm required to maintain an overall relative ratio, do I have to maintain the original quantities that made up the ratio?
    Community Answer
    No. You just have to keep the differences between the numbers proportionate to the increase of the former and latter numbers in the ratio.
  • Question
    I need to find the ration between 980 to 420. How do I calculate ratios?
    Community Answer
    To simplify 980:420, find a common multiple. If there's still a number that divides into the both of them, then continue with that. So in this case, it will be 7. Then you would finish off with the answer of 7:3.
  • Question
    How do I turn 2/10 into a ratio?
    Community Answer
    The numerator is the first number, the denominator is the second number, and a colon goes in the middle, therefore the ratio is 2:10.
  • Question
    The volume of a box with a rectangular base is 3072 cm3, the length of the sides are in the ratio 1:2:3. What is the length of the shortest side?
    Community Answer
    Let a, b, and c represent the lengths of the sides. First, abc = 3072 cm^3. The ratio a:b:c = 1:2:3 gives you two more equations; b = 2a, and c = 3a. Substitute b and c into the original volume equation so that only the single variable a remains. a(2a)(3a) = 3072 cm^3. Solve that by division by 6 and taking cube roots to get a = 8cm. This means b = 16cm and c = 24cm and you can check that this is a solution.
  • Question
    In a school of 120 pupils, 2/3 of them like mathematics. How many pupils do not like mathematics?
    Donagan
    Top Answerer
    If 2/3 of the pupils like math, 1/3 do not. 1/3 of 120 is 40.
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