Two unequal pairs of numbers satisfy the following conditions: (i) The product of the two numbers in each pair is 2160 (ii) The HCF of the two numbers in each pair is 12. If x is the mean of the numbers in the first pair and y is the mean of the numbers in the second pair, then what is the mean of x and y?

Two unequal pairs of numbers satisfy the following conditions: (i) The product of the two numbers in each pair is 2160 (ii) The HCF of the two numbers in each pair is 12. If x is the mean of the numbers in the first pair and y is the mean of the numbers in the second pair, then what is the mean of x and y? Correct Answer 72

Given: 

HCF of the numbers in a pair = 12

Concept Used:
Mean = (First term + last term)/2

Calculation:

Let, the numbers be ‘12p’ and ‘12q’

Product of numbers = 2160

⇒ 12p × 12q = 2160

⇒ pq = 15

This is only possible when the values of p and q are either 1 and 15 or 3 and 5

Hence, the two pairs of numbers are (12, 180) and (36, 60)

⇒ Mean of first pair = x = (12 + 180)/2 = 96

⇒ Mean of second pair = y = (36 + 60)/2 = 48

Mean of x and y = (96 + 48)/2 = 72

∴ Mean of x and y is 72. 

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