Title too long but please help

Question

A bicyclist traveled with a speed of 12 km/h from a camping ground to a station, located 60 km away. Write a formula expressing the dependence of the variable s on t, where s is the distance between the bicyclist and the station in km, t - the duration (time) of his travel in hours. Using the formula, find:

a) s for t = 3.5, the formula is: ? and for t=3.5 s = ?

b) t for s = 30, the formula is: ? and for s = 30 t = ?

Answer 1

Given that the standard equation for distance (here written as s) = rate x time (t here and usually), the equation works out to be s=rt. We can find r by taking the distance and the time then and putting them into the equation. In this case, 60=t(15). Moving the number so t is by itself gives that t=4.

For equation (a), assuming his speed remains unchanged, s=4x3.5. This will make s=14 km.

We can use the standard equation for question (b), 30=4t. Dividing these gives that t is equal to 30/4 which reduces to 15/2 or 7.5 hours.