Question

If t1+t5+t10+t20+t24=225 find the sum of first 24th term of that



a. P.

Answer 1

Answer:

900

Step-by-step explanation:

Given  

If t1+t5+t10+t20+t24=225 find the sum of first 24th term of that a. P.

ANSWER

We know that according to question we get

t 1 + t5 + t10 + t15 + t20 + t24 = 225

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

6t + 69d = 225

2t + 23d = 75

t + (t + 23d) = 75

t + l = 75

So 24 th term = n/2(a + l)

                      = 24/2 x 75

                       = 900

Answer 2

Answer:

900

Step-by-step explanation:

Sn=n/2[2a+(n-1)d]

S24=24/2[2a+(24-1)d]

S24=12[2a + 23d]             eq (1)

now

t1+t5+t10+t20+t24 can we wrriten as (a)+(a+4d)+(a+9d)+(a+14d)+(a+19d)+(a+24d)

so ..

after adding we get

6a + 69d = 225

a=(225-69d)/6

substuting value of a in eq 1 we get:

900