Question

5.How many terms are identical in the two
APs 1,3,5......upto 120 terms and 3,6,9„upto
80 terms?
(a)38
(b)39
(c) 40
(d)41

Answer 1

Refer to the attachment for your solution.....

Answer 2

Answer:

(c) 40

Step-by-step explanation:

First AP:

1, 3, 5, ..... upto 120 terms

a=1, d=2, n=120

Second AP:

3, 6, 9, ..... upto 80 terms

For the identical terms among both the APs,

we observe that the first AP consists of first 120 odd numbers, while second AP consists of first 80 multiples of 3.

For the identical terms, we will have odd multiples of 3 among the first 80 multiples of 3.

Since every alternative multiple of 3 is odd, we will have 80/2 = 40 identical terms.