Correct option is (A) 20 and (B) 50/3
Given f = 10 cm
Let R = 2f
v = -2f
v = -2 x 10
VA = -20 cm
For B u = -25
f = -10
\(\frac1v=\frac1f-\frac1u\)
\(\frac1v=\frac1{-10}+\frac1{25}\)
\(\frac1v=\frac{-25+10}{250}\)
\(\frac1v=\frac{-15}{250}=\frac{-3}{50}\)
\(\frac1v=-\frac3{50}\)
VB = -50/3