Answer
$4$ times as many
Work Step by Step
To answer " how many times is ... greater than ... ?", we divide the two data points:
$\displaystyle \frac{3\times 10^{10}}{7.5\times 10^{9}}=\frac{3}{7.5}\cdot\frac{10^{10}}{10^{9}}$
$=\displaystyle \frac{30}{75}\times 10^{10-9}$
$=\displaystyle \frac{2}{5}\times 10^{1}$
$=2\times 2$
= $4$ times as many
