Question

find the sum of 30 terms of a.p 5+10+15+........​

Answer 1

Step-by-step explanation:

AP 5+10+15+.............….

S(30)=?

n=30

tn=a+(n-1)d

=5+29×5

=150

Sn=(a+l)/2

(5+150)/2

155/2=77.5

Answer 2

Answer:

To find sum

Sn = n/2 (2a+(n-1)d)

n = 30, a= 5, d= 5

Sn = 30/2 {2(5) + (30-1)5}

=> 15 {10+145}

=> 15×155

= 2325

Sn = 2325

hope it's helpful.