The average of first four out of five given numbers is 15 and that of the last…
2025
The average of first four out of five given numbers is 15 and that of the last four is 16. If the last number is 20, the first one is?
- A.
15
- B.
16
- C.
18
- D.
19
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Correct answer: B
Solution:
Let the five numbers be a, b, c, d, 20.
Average of the first four is 15, so a + b + c + d = 60.
Average of the last four is 16, so b + c + d + 20 = 64, which gives b + c + d = 44.
Subtracting the second equation from the first gives a = 60 - 44 = 16.
Answer: 16