#### Answer

For approximately $1,650,361$ high school teenagers, doing well in school is the most important problem.

#### Work Step by Step

The graph shows data for $16,503,611$ students in the United States.
Out of those students, the graph shows that for $11\%$, doing well in school is the most important problem.
$11\%$ is approximately $10\%$, which is $\frac{1}{10}$; therefore, without using a calculator, we can estimate:
For about $16,503,611*\frac{1}{10}\approx1,650,361$ high school teenagers, doing well in school is the most important problem.