Question

The first term of an arithmetic progression is unity and the common difference is 4. Which of the following will be a term of this A.P.

विकल्प

• 4551

• 10091

• 7881

• 13531

Answer 1

7881

Explanation;

t₁ = 1

d = 4

t_n = a + (n – 1)d

= 1 + 4n – 4

4n – 3 = 4551

4n = 4554

n = will be a fraction

It is not possible.

4n – 3 = 10091

4n = 10091 + 3 = 10094

n = a fraction

4n – 3 = 7881

4n = 7881 + 3 = 7884

n = `7884/40`, n is a whole number.

4n – 3 = 13531

4n = 13531 – 3

= 13534

n is a fraction.

∴ 7881 will be 1971^st term of A.P.