the sum of a1+a5+a10+a15+a20+a24=225 find the sum of this a1+a2+a3.........a23+a24=? how to solve this question?

Answer 1

mathematics

Answer 2

You already have the sum of 225. Typos? But you could add them.

75a = 225

To find a, divide both sides by 75.

Answer 3

assuming that all the a's are terms of an arithmetic progression, you have
a1+a5+a10+a15+a20+a24 = 6a+69d = 225
Now you want to find
S12 = 12/2 (2a+23d) = 24a+276d = 4(6a+69d) = 4*225 = 900