Answer
$\frac{3}{8}$ lb
Work Step by Step
Given a new born baby is expected to loose $\frac{1}{20}$ of its body weight during first week
if the weight of the baby = 7$\frac{1}{2}$ lb
therefore we need to find the weight lose by the baby = $\frac{1}{20}$ x 7$\frac{1}{2}$ lb
=$\frac{1}{20}$ x $\frac{15}{2}$
=$\frac{3}{8}$ lb
