Question

the last term of the series 5, 7, 9, .....to 21 terms is​

Answer 1

AP = 5, 7, 9.....

First term (a) = 5

Common Difference ( d ) = 7 - 5 = 2

Total number of terms (n) = 21

Last term = a + ( n - 1 ) d

= 5 + ( 21 - 1 ) 2

= 5 + ( 20 ) 2

= 5 + 40

= 45

Therefore last term or the 21st term of the given AP is 45.