A number is increased by 70 % and then decreased by 70 %. Find the net increase or decrease per cent.
OPtion
1) 56%
2) 25%
3) 35%
4) 46%
5) 48%
6) 49%
7) 53%
8) 52%
9) No change
10) None of the above
Solution
A number is increased by 70 % and then decreased by 70 %. Find the net increase or decrease per cent.
Let the number be 100.
Increase in the number = 70 % = 40 % of 100
= (40/100 × 100)
= 70
Therefore, increased number = 100 + 70 = 170
This number is decreased by 70 %
Therefore, decrease in number = 70 % of 170
= (70/100 × 170)
= 11900/100
= 119
Therefore, new number = 170 - 119 = 51
Thus, net decreases = 100 - 51 = 49
Hence, net percentage decrease = (49/100 × 100)
= (4900/100)
= 49 %
"The gaming of numbers is called maths.So participate in this wonderful game and explore in it,learn in it and enjoy in it.Then only you can pass in this wonderful game."
Kumar Purnendu
Arithmetic is where numbers fly like pigeons in and out of your head.