Question

7,15,23,31 find the 78th term

Answer 1

The 78th term is 623

Explanation:

Given:

a₁ = 7; a₂ = 15; a₃ = 23 and so on.

n = 78

To Find:

a₇₈ = ?

Now, Common Difference d

d = a₂ - a₁ = 15 - 7 = 8

d = a₃ - a₂ = 23 - 15 = 8

Here, The Common Difference is same everywhere.

So,

aₙ = a + (n - 1) d

a₇₈ = 7 + (78 - 1) × 8

a₇₈ = 7 + (77) × 8

a₇₈ = 7 + 616

a₇₈ = 623

Thus, The 78th term is 623

-TheUnknownScientist 72

Answer 2

623 is the answer

Explanation:

equation : 8X-1

8(1)-1 = 7

8(2)-1 = 15

8(3)-1 = 23

8(4)-1 = 31

8(78)-1 = 623