Solution:
we are given that
Two months ago a car dealership sold 150 cars.Thirty of them were red .
Last month ,the dealership sold 200 cars.
Using unitry method , we can say that
30 cars were red out of 150.
So if there were only one car then there will be
red cars.
So if there are 200 cars then there wil be
red cars.
Hence there will be 40 red cars.