A ball is dropped from a height of 10m. Each time it strikes the ground it bounces vertically to a height that is 3/4 of the preceding height. Find the total distance the ball will travel if is assumed to bounce infinitely often

I get 40m as my answer but the back of the book says 70m

this is what im doing.

$\displaystyle \sum_{k=0}^{\infty}10*(\frac{3}{4})^k$

with $\displaystyle r=\frac{3}{4};a=10$

$\displaystyle \frac{10}{1-\frac{3}{4}}= \frac{10}{\frac{1}{4}}$

=40m