In a set of three numbers, the average of first two numbers is 21, the average of the last two numbers is 24, and the average of the first and the last numbers is 15. What is the average of three numbers?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 20
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Understanding |
Application |
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In a set of three numbers, the average of first two numbers is 21, the average of the last two numbers is 24, and the average of the first and the last numbers is 15. |
Suppose the numbers are p, q and r. So, (p + q) = 21 × 2 = 42 (q + r) = 24 × 2 = 48 And (p + r) = 15 × 2 = 30 Adding the equations: 2(p + q + r) = 120 (p + q + r) = 60 Average = 60/3 = 20 |