Question

Find the sum of first 50 terms of the sequence 5, 5.5, 5.55,........

Answer 1

Sn =n/2(2a +(n-1)d
Here n =50
a =5
d=5.5-5=0.5
Putting in formula
S50 =50/2(2×5+(50-1)0.5
=25(10+(49)×0.5)
=25(10+24.5)
=25(34.5)
=862.5