Question
The mean of a set of 8 numbers is 80. If the average of
the first four numbers and the last two numbers is 90 and 60, respectively, and the ratio of the fifth number to the sixth number is 3:2, what is the value of the fifth number?Solution
ATQ, Let fifth and sixth numbers be ‘3a’ and ‘2a’, respectively. So, 3a + 2a = (80 × 8) – (90 × 4) – (60 × 2) = 160 Or, 5a = 160 Or, a = 32 So, fifth number = 32 × 3 = 96
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