Question

find the sum of 100 terms of the AP 0.7,0.71, 0.72

Answer 1

the correct ans is 56.5
S = ½(2a + (n-1)d)n
S = ½(2*.7 + (99)*.01)100
S = 50(.14 + (99)*.01)
S = 50(.14 + .99)
S=56.5

Answer 2

first term = 0.7

common difference = 0.01

sum of 100 terms =100/2 ( 2×0.7 + 99 × 0.01)
= 50 ( 1.4 + 0.99)

= 50 ( 2.39)

= 119.5