To find the number of people who chose black we do
18/100 x 150 which is 27/100
27
27 is 18% of 150
We do the same to find who chose white but instead of 18 we use 24
24/100 x 150 = 37
37 out of 150 chose white
27 out of 150 chose black
37 - 27 = 10
Ten more people chose white than black.