Question

Evaluate - 7+11+15+..... to 29 terms. (This question is related to Arithmetic Progression.)

Answer 1

N th of an A.P is given by, An= first term 'a' + (n-1) common difference 'd'.
therefore A29=7+(29-1)*4
<=>29th term =119

now sum of N terms =N/2(first term'a'+last term'l')
here first term=7 and last term=119
therefore sum of 29 terms =29/2(7+119)=1,827


I hope this will help you