Question

52 packets contains 12 pencil each cost rs 499.20 .find the cost of 65 packets containing 10 pencil each

Answer 1

52 packets with 12 pencils each,cost Rs 499.20.find the cost of 65 packets of 10 pencils each.
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52 packets of 12 pencils each is 52×12 or 624 pencils
So if Rs 499.20 is the price of 624 pencils, then 1 pencil costs
499.20 ÷ 624, or Rs 0.80.
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65 packets of 10 pencils each is 65×10 or 650 pencils
So since 1 pencil costs Rs 0.80, then 650 pencils costs 650×0.80 or Rs 520. 

Answer 2

(52×12) =624 pencils cost = 499.20
then,
1 pencil cost = 499.20/624 = 0.8
hence,
(65×10)=650 pencils cost = 650×0.8= 520

I Hope this will help you..