Choose the one alternative that best completes the statement or answers the question.
Solve the problem. Round your answer, as needed.
-A formula for the focal length of a lens is
$\mathrm{f}=\frac{\mathrm{ab}}{\mathrm{b}+\mathrm{a}}$
Calculate $\mathrm{f}$ (the focal length) for $\mathrm{a}=8 \mathrm{~cm}$ and $\mathrm{b}=15 \mathrm{~cm}$.
A) $5.2 \mathrm{~cm}$
B) $2.8 \mathrm{~cm}$
C) $7.5 \mathrm{~cm}$
D) $4.0 \mathrm{~cm}$

Question

Quizplus · Accepted Answer

The Answer of Choose the one alternative that best completes the statement or answers the question.
Solve the problem. Round your answer, as needed.
-A formula for the focal length of a lens is
$\mathrm{f}=\frac{\mathrm{ab}}{\mathrm{b}+\mathrm{a}}$
Calculate $\mathrm{f}$ (the focal length) for $\mathrm{a}=8 \mathrm{~cm}$ and $\mathrm{b}=15 \mathrm{~cm}$.
A) $5.2 \mathrm{~cm}$
B) $2.8 \mathrm{~cm}$
C) $7.5 \mathrm{~cm}$
D) $4.0 \mathrm{~cm}$

Choose the One Alternative That Best Completes the Statement or Answers