Question

Find the sum of the series 5+8+11..........+68

Answer 1

Answer:

803(Answer above my answer is incorrect)

Step-by-step explanation:

a = 5

d = 8-5 = 3

t = a + (n-1)d

68 = 5 +(n-1)3

68 = 5+ 3n - 3

68 = 2 + 3n

66 = 3n

n = 66/3

n = 22

NOW

Sum = n/2(a+l)

Sum = 22/2(5+68)

Sum = 11(73)

Sum = 803