24:32 is the ratio. Just add up he total number and then put the total number of student over the total number of people
So to to get 3% of 159 you: 159x0.03=4.77
I think it is -2288 something like that
The sum of the first n natural numbers and 0=
n*(n+1)/2
(a) P( fifth one is bad) = P( first 4 are OK) * P(5th is bad)
= (0.98)^4 * 0.02 = 0.0184 or 1.84%
(b) this will be (0.98)^10 = 81.70%