Question

the first term for an AP is 1 and the sum of first 15 term is 225 find common difference​

Answer 1

Step-by-step explanation:

a=1

s15=225

s15=(n/2)(2a+(n-1)d)

225=(15/2)(2(1)+(15-1)d)

225=(15/2)(2+14d)

225*2/15=2+14d

14d+2=450/15

14d+2=30

14d = 30-2

d=28/14

d=2

Answer 2

a=1

s15=225

s15=(n/2)(2a+(n-1)d)

225=(15/2)(2(1)+(15-1)d)

225=(15/2)(2+14d)

225*2/15=2+14d

14d+2=450/15

14d+2=30

14d = 30-2

d=28/14

d=2