At the beginning of the summer, Aidan was $160 \mathrm{~cm}$ tall. At the end of the summer, he measured his height again and discovered that it had increased by $5 \%$. Measured in $\mathrm{cm}$, what was his height at the end of summer?
(A) 168
(B) 165
(C) 160.8
(D) 172
(E) 170
Solution 1

ANSWER: (B)

A $5 \%$ increase in 160 is equal to $\frac{5}{100} \times 160$ or $0.05 \times 160=8$.

Therefore, Aidan's height increased by $8 \mathrm{~cm}$ over the summer.

His height at the end of the summer was $160+8=168 \mathrm{~cm}$.

Solution 2

Since Aidan's $160 \mathrm{~cm}$ height increased by $5 \%$, then his height at the end of the summer was $\left(1+\frac{5}{100}\right) \times 160=(1+0.05) \times 160=1.05 \times 160=168 \mathrm{~cm}$.