How to solve a school held a jump ropeing contest. diego jumped rope for 20

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)

Two trains leave a station on different tracks. the tracks make an angle of 130°, with the station as a vertex. the first train travels 100 km and makes its first stop at point a, while the second train travels 200 km and makes it first stop at point b. how far apart are the trains when both are at their first stop? round the answer to the nearest integer. a) 65 km b) 139 km c) 224 km d) 275 km

Asap 30 pts + brainliest to right/best answer