Multiple choice

Choose the correct answers from the alternatives given. The average age of three boys is 15 years. If their ages are in the ratio of 3 :5 :7. then the age of the youngest boy (in years) is

  1. 15

  2. 18

  3. 21

  4. 9
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sum of ages = 15 * 3 = 45. Ratio 3:5:7 means 3x + 5x + 7x = 45. 15x = 45, so x = 3. Youngest boy = 3x = 9.

AI explanation

The total age of the three boys is 15 times 3, which equals 45 years. Let their ages be 3x, 5x, and 7x based on the given ratio. The sum of these parts is 15x, so 15x equals 45, meaning x is 3. The youngest boy's age is 3x, which calculates to 9 years.

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