Question

in an ap the first term is 2 and sum of first 5 is one fourth of the sum of next 5 show that 20th term is -112​

Answer 1

Step-by-step explanation:

-112=2+19d

-114=19d

d=-6

S5=5/2(4+4x-6)

=5/2x-20

=-50

S10=10/2(4+9x-6)

=5x-50

=-250

S5/S10-S5

-50/-250+50

-50/-200

1/4