Two concave lenses of 60 cm focal length are cemented on either side of a convex lens of 15 cm focal length. The focal length of the combination is

AI-generated answer
Substitute the values into the formula: 1/f(combined) = 1/60 + 1/60 + 1/15 1/f(combined) = 1/60 + 1/60 + 4/60 1/f(combined) = 6/60 1/f(combined) = 1/10 Therefore, the focal length of the combination is 10 cm. Hence, the correct answer is (A) 10 cm.