Question

137. The sum of 11 + 12 + 13 + 14 ...... + 60 will be
(a) 1830
(b) 1775
(c) 1875
(d) 182
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Answer 1

Answer:

a= 11, d= 12-11=1, Let 60 be its nth term.

an= 60

Explanation:

a+(n-1)d=60

11+(n-1)1=60

11+n-1=60

n=60-10

n=50

Sn= n/2(2a+(n-1)d)

S50= 50/2(2*11+(50-1)1)

S50= 25(22+49)

S50= 25*71

S50= 1775

Hence B is the correct option.

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