Question

The sum of the first twelve terms of an arithmetic sequence is 522.The sum of the first sixteen terms is 880.Find the common difference of this sequence.

Answer 1

Answer:I think answer is 23/4

Step-by-step explanation:

Look at the image

Answer 2

Answer:

d = 37/6

Step-by-step explanation:

we know that

sum of n terms of an ap= n/2(2a+(n-1)d)

where a is the first term of an ap, n is the total number of terms and d is the common difference.

using the given information we obtain

522=12/2(2a+(12-1)d) ....eqn (1)

880=16/2(2a+(16-1)d) ....eqn(2)

now on solving the above equations further we get:

522=12a+66d .....(3)

880=16a+120d .....(4)

now multiply equation (3) by 4 and multiply equation (4) by 3

we get

2088=48a+264d

2640=48a+360d

solving the above equations we get

552=96d

d=552/96=23/4