Answer
a. about $48\%$
b. $48.1\%$
c. year $2036$
Work Step by Step
a. Use the lower curve (purple) for women and read at the year 2010 to get a percentage value of about $48\%$.
b. Given the formula $p=1.6\sqrt t+38$ and the year $t=2010-1970=40$, we have $p=1.6\sqrt {40}+38\approx48.1(\%)$
c. Let $p=51(\%)$; we have $1.6\sqrt t+38=51$ and $1.6\sqrt t=13$, which gives $t\approx66$ years. This corresponds to year $1970+66=2036$.
