- Total timeof Ndiba =1+3=4hours

Let
- Ndibas speed be x
- Willies speed=x+10
Both travelled same distance



It’s 180 = 100 + angle 1.
There is a 1/2 probability that the number will be divisible by 2 because there are 5 numbers from 1 to 10 divisible by 2. So 5/10 = 1/2.