how do you solve these maths problems? someone explain to me??

Question

1. The driver of a car travelling at 60 km/h is 80 km behind the driver of another car travelling at 50 km/h. How long will it take the faster car to catch up with the slower car?

2. Find the volume of water in a cylindrical tank of diameter 1.4 m and height 60 cm. This water is poured into a rectangular trough of length 1.2 m and width 80 cm. Find the height of water in the trough. ( Take π = 22/7 )

Answer 1

Ans 1: As we know that S = v*t.
Assume that the distance of the slower car is S from where the fast car catches up.

Then,
Case I: S = 50*t (for slower car).
Case II: S+80=60*t (for faster car).

Subtracting I from II, we get:
80=10*t
or t = 8 hours.
Hence, it takes 8 hours for the fast car to catch the slower car.

Ans 2: Volume of the cylinder=π *(r^2)*h
In this case r = 70 cm and h = 60 cm.
Therefore, volume is 22/7*70*70*60=924000 cm cubed.
Now, volume of the tank is l*b*h.
Therefore 924000=120*80*h
Therefore h = 96.25 cm.