Question 52339
when a number is decreased by 30% the result is 140, what is the number? 

Lets begin by assuming the original number to be X.
Then according to the statement :
 
 X-(30/100)*X= 140

Multiply be denominator 100 on both sides we get,
100X-30X= 14000
70X=14000
i.e X=14000/70=200
Therefore the value of X=200

Cross Verification
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30% of 200 is 200*30/100=60
Decreasing 200 by 60 we get, 200-60 =140


2) when 50% of a number is added to it the result if 180
Let original number be X.
In this case we get,
 X+(50/100)X=180
Solving using above way we get X=120

Cross Verification
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50% of 120 is 120*50/100=60
Adding  60+120=180