Question

In a sequence if Tn = 5n² - 4 What is the sum of the 5th and 7th terms?

a)121
b)244
c)365
d)367​

Answer 1

d)367

Explanation:

Given, Tn = 5n² - 4

To find the 5th term, substitute n = 5 in the equation Tn = 5n² - 4

T5 = 5(5)² - 4

T5 = 121

To find the 7th term, substitute n = 7 in the equation Tn = 5n² - 4

T7 = 5(7)² - 4

T7 = 241

Therefore, the sum of the 5th and 7th terms = T5 + T7 = 121 + 241 = 362.

Hence, the correct option is (d) 367.