Question

determine a soma do múltiplo de 5 compreendidos 8 e 198

Answer 1

a₁ = 10

an= 195

r = 5

an = a₁ + (n - 1) . r ------ 195 = 10 + (n - 1) . 5 ------ 195 - 10 = (n - 1) . 5 

185 = (n - 1) . 5 --- 185/5 = (n - 1) ----- 37 = n - 1 ---- n = 37 + 1 ------ n = 38

S₃₈ = [(10 + 195) . 38]/2 ----- S₃₈ = (205) . 19 ------ S₃₈ = 3895