Question

find the sum of first 24 terms of the AP a1,a2,a3....an if it is known that a1+a5+a10+a15+a20+a24=225​

Answer 1

Answer:

900

Step-by-step explanation:

LET FIRST TERM=a, COMMON DIFFERENCE=D

a1+a5+a10+a15+a20+a24=225​

a+a+4d+a+9d+a+14d+a+19d+a+23d=225

6a+69d=225

2a+23d=75----------------(1)

Now sum of 24 terms

S24=24/2(2a+23d)

=12*(75)

=900