Number of person who like coffee, `n(A) = 37`
Number of person who like tea, `n(B) = 52`
As each person likes at least one of the two drinks,
`n(AuuB) = 70
`
Number of person who like both coffee and tea,
`n(AnnB) = n(A)+n(B)-n(AuuB) = 37+52-70 = 19`