Question

2. Which term of the A. P.: 5, 11, 17, is 119?

Answer 1

Answer:

ᴡʜᴇɴ ᴀ (ꜰɪʀꜱᴛ ᴛᴇʀᴍ ) = 5, ᴅ (ᴅɪꜰꜰᴇʀᴇɴᴄᴇ) = 6

ᴛʜᴇɴ ɴᴛʜ ᴛᴇʀᴍ = 

ᴀ(ɴ) = ᴀ + (ɴ-1)ᴅ

119 = 5 + (ɴ-1)6

(ɴ-1)6 = 114

ɴ-1 = 114/6 = 19

ɴ = 20

Answer 2

119 is the 20th term of the A.P.

Given,

An arithmetic progression 5, 11, 17,...

To Find,

Which term of the A.P is 119.

Solution,

In the given A.P

5, 11, 17,...

a = 5

d = 11-5 = 6

Now, we have to find that 119 is which term of A.P

The formula of the nth term of A.P is

aₙ = a+(n-1)d

So, aₙ = 119

119 = a+(n-1)d

119 = 5+(n-1)6

6n-6 = 114

6n = 120

n = 120/6

n = 20

Hence, 119 is the 20th term of the A.P.

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