Question

Q1 the ratio of cost price and selling price of an article is 20:21. what is the gain % on it ??

Q2 decrease 160 by 12.5

Q3 what must be subtracted from 6a2 -3ab -3b2-1 to get

4a2 -7ab -4b2 +1?

note that 2 after the variable is square or power .

Answer 1

1) Let the cost price and selling price of the article be 20k and 21k respectively. So gain=21k-20k=k .
Gain% =k/20k ×100 =5% .
2) 160-12.5 =147.50.
3) let the quantity to be subtracted be x => 6a2-4ab-3b2-1 -x = 4a2-7ab-4b2+1 => x= 4a2-7ab-4b2 +1-(6a2-4ab-3b2-1 ) = -2a2-3ab-b2 +2 .
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