Question

Find S30 , if first term of A.P is 10 and common difference 5.

Here, a=10 d=5 s30=?



Sn = [ +( − 1)]

2

Sn= ]

= 15[ 20 + ]

= 15 *

S30

​

Answer 1

Answer:

2475

Step-by-step explanation:

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

S30 = 30/2 [ 2(10) + (30-1) ×5]

= 15 [ 20 + (20×5)]

= 15 [ 20 + 145]

= 15 × 165

= 2475