Question

12. The last term of the series 5, 7, 9,..... to 21 terms is
(a) 44
(b) 43
(c) 45
(d)none of these

Answer 1

formula to find last term = a+(n-1) * d

a = first term = 5

d = second term - first time

d = 7-5

d = 2

To find 21 st term

21 st term = a+(n-1) *d

= 5+(21-1)*2

= 5+(20*2)

= 5+40

= 45 (option C)

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Answer 2

Answer:

option (c) 45

Step-by-step explanation:

first term is 5

command difference is 2

number of term =n=21

tn is last term

tn=a+(n-1)d

=5+(21-1)2

= 5+20×2

=5+40

= 45