Question

how we will solve rupees 55125 ×100/105 ×100/105
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Answer 1

Answer:

The sum of 5+10+15 ….+100 is the sum of an AP whose first terms is 5, the last term is 100 and the common difference is 5.

Th = 100 = a +(n-1)d = 5 +(n-1)5 = 5

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

= (20/2)[2*5+ (20–1)*5]

= 10[10+95]

= 10*105

= 1050