Question

in an ap of 15 terms the sum of 10 terms is 210 and the sum of its last 15 term is 265 find the AP

Answer 1

a10=210 and a15=265
a+9d=210. (eq.1)
a+14d=265. (eq.2)
from eq.1 , a=210-9d
now putting these term in eq.2
a+14d=265
210-9d+14d=265
210+5d=265
5d=265-210
5d=50
'd=50'


now, a=210-9d
a=210-9(50)
a=210-450
'a=-240'

Answer 2

step by step solution

a15=265

a+14d=265. ---(1)

a10=210

a+9d=210. ----(2)

substract from equationt. (1) to (2)

5d=265-210

5d=55

d=11

a=210-9d
a=210-9x11
a=210-99
a=111

now your ap is...
111,122,133,144,155,166,177,188,199,210,221,232, 243,254,265

Thank you dear
hope it's helpful