Question

Which number should be added to the numbers 13, 15, 19 so that the resulting numbers be the consecutive terms of a H.P.

• A. 7
• B. 6
• C. -6
• D. -7

Answer 1

The correct option is D

-7

Suppose that x to be added the numbers 13, 15,19 so that new numbers x + 13, 15 + x, 19 + x will be in H.P.

$\Rightarrow (15+x)$ = $\frac{2(x+13)(19+x)}{(x+13+x+19)}$

$\Rightarrow x^2+31x+240$ = $x^2+32x+247\Rightarrow x$ = -7

Trick:Such type of questions should be checked with the options.