Question

Find the sum of the first 50 terms of the arithmetic series: 1, 4, 7, 10, 13, … 2,900 3,550 3,725 4,225

Answer 1

1, 4, 7, 10, 13, . . .
a = 1, d = 4 - 1 = 3, n= 50
Sn = n/2[2a + (n - 1)d] = 50/2[2(1) + (50 - 1)3] = 25[2 + 49(3)] = 25[2 + 147] = 25(149) = 3,725