Question

which term in the A.P 3, 8, 1 point
13, 18,......... is 148? *
O (A)150
O (B) 149
O (C) 30
O (D) 29​

Answer 1

$\huge\fbox\pink{AnsweR}$

a = 3

d = a2 - a1

d = 8 - 3

d = 5

an = 148

an = a + (n - 1)d

148 = 3 + (n - 1) 5

148 = 3 + 5n - 5

148 = -2 + 5n

148 + 2 = 5n

5n = 150

n = 150 ÷ 5

n = 30

So, the 30th term is 148.

Answer 2

Answer :

• Option (C) 30

S O L U T I O N :

Given,

• AP :- 3,8,13,18,.....148

• First term (a) = 3

Common difference (d) = Second term - First term

=> d = 8 - 3

=> d = 5

• Common difference (d) = 5

• a_n = 148

To Find,

• Which term is the 148.

Explanation,

nth term of an AP,

=> a_n = a + (n - 1)d

[ Put the values ]

=> 148 = 3 + (n - 1) × 5

=> 148 = 3 + 5n - 5

=> 148 = -2 + 5n

=> -5n = -2 - 148

=> -5n = -150

=> n = 30

Therefore,

The 30th term is 148.

For information,

• S_n = n/2 × (2a + (n - 1)d)
• S_n = n/2 × (a + l)