I found this for you. It even tells you how the answer was achieved.
P(

successes in

trials) = ⁿ

×
![[P(Success)^{r}]](https://tex.z-dn.net/?f=%20%5BP%28Success%29%5E%7Br%7D%5D%20)
×
![[P(failure)]^{n-r}](https://tex.z-dn.net/?f=%20%5BP%28failure%29%5D%5E%7Bn-r%7D%20)
We have




Substitute these values into the formula, we have
P( 2 success in 8 trials) = ⁸C₂ × (0.15)² × (0.85)⁶
P( 2 success in 8 trials) = 0.2376.... ≈ 0.24 = 24%