Question

please solve this question......​

Answer 1

Let P be the power of the combination.

Let P1 be the power of the first lens, P1 = 1.5D

Let P2 be the power of another lens,

So P = P1 + P2

P = 1.75D.

1.75 = 1.5 + P2

P2 = 1.75 - 1.5 = 0.25

So another lens of power 0.25 D should be combined with the lens to give a power combination of 1.75.