If the mean proportional of 18 and 98 is 2A + 6, the value of A is:
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Correct answer: D
Explanation
The correct answer is Option 4 i.e. 18.
Mean proportional of 18 and 98 = √(18 × 98) = √1764 = 42
mean proportional = 2A + 6
So, 2A + 6 = 42
2A = 36
A = 18