Problem-Solving and Data AnalysisEasyScaling a ratio
Problem-Solving and Data Analysis practice question
In a bag of marbles, the ratio of red marbles to blue marbles is 3 to 5. If there are 24 red marbles, how many blue marbles are there?
- A. 40Correct
- B. 14.4
- C. 8
- D. 15
Answer: A. 40
The ratio 3 to 5 means every 3 red marbles go with 5 blue ones. 24 red is 8 groups of 3, so there are 8 groups of 5 blue: 8 × 5 = 40. (Or set up the proportion 3/5 = 24/x and solve: x = 24 × 5 / 3 = 40.)
Why the other answers are wrong
- B. 14.4
- 14.4 is 24 × 3/5 — the ratio was applied upside down. Blue is the LARGER part (5 to red's 3), so there must be more than 24 blue marbles, not fewer.
- C. 8
- 8 is how many groups of 3 fit into 24 red marbles — a useful step, but each group brings 5 blue marbles, so multiply 8 by 5.
- D. 15
- 15 is 3 × 5, the two ratio numbers multiplied together. The ratio has to be scaled up to match the 24 red marbles first.
More Problem-Solving and Data Analysis questions
- Easy
What is 40% of 150? - Easy
A class has 25 students, and 60% of them play a sport. How many students play a sport? - Easy
A runner covers 3 kilometers. Given that 1 kilometer equals 1000 meters, how many meters is this? - Easy
What is the range of the number of hours worked by these 6 volunteers? - Easy
A shirt has a price of $24.00. A sales tax of 8% of the price is added to the price. What is the total cost, i… - Easy
If one of these 80 students is selected at random, what is the probability that the student chose Music?
Not affiliated with the College Board. SAT is a trademark of the College Board.