Question

If 6th term of an ap is -10and it's 10th term is -26,then find the 15 th term of an ap.

Answer 1

Answer:

15th term of AP = -46

Step-by-step explanation:

nth term of AP is given as

Tn = a + (n - 1)d

where, a = first term

            d = common difference

            n = nth term

Given that 6th term of AP is -10

We have,

T6 = -10

a + (6 - 1)d = -10

a + 5d = -10 -------- (1)

Also, given that 10th term of AP is -26

We have,

T10 = -26

a + (10 - 1)d = -26

a + 9d = -26 --------- (2)

Solving the (1) and (2), we get

 a + 5d = -10

 a + 9d = -26

(-)  (-)        (+)

----------------------

     -4d  = 16

        d = -4

Substituting the value of d = -4 in (1), we get

a + 5(-4) = -10

a - 20 = -10

a = 10

Hence, we get a = 10 and d = -4

Now, 15th term of AP is calculated as

T15 = a + (15 - 1)d

T15 = 10 + 14(-4)

T15 = 10 - 56

T15 =  -46

Answer 2

Answer:

for this question the value of a=10 and b=-4

and T15= -46