Question

The first three terms of an A.P. respectively are 3y – 1, 3y + 5 and 5y + 1. Then, y equals
A. –3
B. 4
C. 5
D. 2

Answer 1

The required "option C) 5" is correct.

Step-by-step explanation:

The given first three terms of an A.P. are:

3y - 1, 3y + 5 and 5y + 1

Here, first term = 3y - 1, second term = 3y + 5 and third term = 5y + 1

To find, the value of y is equal to

We know that,

Common difference (d) = Second term - First term = Third term - Second term

∴ 3y + 5 - (3y - 1) = 5y + 1 - (3y + 5)

⇒ 3y + 5 - 3y + 1 = 5y + 1 - 3y - 5

⇒ 5 + 1 = 2y - 4

⇒ 6 = 2y - 4

⇒ 2y = 6 + 4 = 10

⇒ y = $\dfrac{10}{2}$ = 5

Thus, the required "option C) 5" is correct.