Answer
a. about $52\%$
b. $51.9\%$
c. year $2036$
Work Step by Step
a. Use the top curve (blue) for men and read at year 2010 to get a percentage value of about $52\%$.
b. Given the formula $p=-1.6\sqrt t+62$ and the year $t=2010-1970=40$, we have $p=-1.6\sqrt {40}+62\approx51.9(\%)$
c. Let $p=49(\%)$. We have $-1.6\sqrt t+62=49$ and $1.6\sqrt t=13$, which gives $t\approx66$ years. This corresponds to year $1970+66=2036$.
