Question

Quantos múltiplos de 3 existem entre 13 e 151?

Answer 1

Trata-se de uma PA (15, 18, 21...150)

an = a1 + (n-1)r
150 = 15 +3(n-1)
150 - 15 = 3n - 3
135 - 3 = 3n
3n = 132
n = 44

Logo existem 44 múltiplos de 3 no intervalo indicado

Answer 2

15,18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,78,81,84,87,90,93,96,99,102,105,108,111,114,117,120,123,126,129,132,135,138,141,144,147,150