The nth term of a sequence is 2n + 1 The nth term of a different sequence is 3n - 1

Work out the three numbers that are in both sequences and also between 20 and 40

The three numbers are 23, 29 and 35.

Step-by-step explanation:

Given: The nth term of a sequence is 2n+1 and the nth term of a different sequence is 3n-1.

To find: The three numbers that are in both sequences and also between 20 and 40.

Consider both the sequences.

Put n = 11 in the nth term 2n+1, we get 23.

So, the 11th term of first sequence is 23.

Now put n = 8 in the nth term 3n-1, we get 23.

So, the 8th term of the second sequence is 23.

Therefore, first number that is in both sequence and lies between 20 and 40 is 23.

Now put n = 14 in the nth term 2n+1, we get 29.

So, the 14th term of first sequence is 29.

Put n = 10 in the nth term 3n-1, we get 29.

So, the 10th term of the second sequence is 29.

Therefore, second number that is in both sequence and lies between 20 and 40 is 29.

If we put n = 17 in the nth term 2n+1, then we get 35.

That is, 17th term of first sequence is 35.

Now we put n = 12 in the nth term 3n-1, then we get 35.

That is, 12th term of second sequence is 35.

So, third number that is in both sequence and lies between 20 and 40 is 35.

Hence, the three numbers that are in both sequences and also between 20 and 40 are 23, 29 and 35.

45

step-by-step explanation: