In a class of 35 ,20 student offer physics ,18 offer chemistry and 2 neither offer the subjects

Illustrate it on the Venn diagram
How many students offer all two subjects
How many student offer only one subject.

p + c + b ... 35 - 2 = 33

p + c + 2 b = 38 ... b = 5

p + 5 = 20 ... p = 15

c + 5 = 18 c = 13