A number is increased by 40 % and then decreased by 40 %.
A number is increased by 40 % and then decreased by 40 %. Find the net increase or decrease per cent.
Answer/Solution
16%
Steps/Work
Let the number be 100.
Increase in the number = 40 % = 40 % of 100
= (40/100 × 100)
= 40
Therefore, increased number = 100 + 40 = 140
This number is decreased by 40 %
Therefore, decrease in number = 40 % of 140
= (40/100 × 140)
= 5600/100
= 56
Therefore, new number = 140 - 56 = 84
Thus, net decreases = 100 - 84 = 16
Hence, net percentage decrease = (16/100 × 100) %
= (1600/100) %
= 16 %
Answer:E
Increase in the number = 40 % = 40 % of 100
= (40/100 × 100)
= 40
Therefore, increased number = 100 + 40 = 140
This number is decreased by 40 %
Therefore, decrease in number = 40 % of 140
= (40/100 × 140)
= 5600/100
= 56
Therefore, new number = 140 - 56 = 84
Thus, net decreases = 100 - 84 = 16
Hence, net percentage decrease = (16/100 × 100) %
= (1600/100) %
= 16 %
Answer:E