Question

In an arithmetic series S10 = 24 and t10 = 42. Find t1 and t2.

Answer 1

Here,

S10 = 24

t10 = 42.

Now, As we know that

Sn = n/2 * (a+l)

Here, n = 10 , l = t10 = 42.

=> 24 = 10/2 * (a+ 42)

=> 24 = 5(a+42)

=> 24 = 5a + 210

=> 5a = 24-210 = -186

=> a = -186/5 .

Now, we will find d as

tn = a + (n-1)d

=> 42 = -186/5 + ( 10-1) d

=> 42 = -186/5 + 9d

=> 42*5 = -186 + 45d

=> 210 + 186 = 45d

=> d = 396/45 = 44/5

t2 = -186/5 + 44/5 = -142/5

Thus, t1 = -186/5 and

t2 = -142/5