Question

a number is first increased by 20% and then decreased by 15% find the net increase or decrease doesn't make any difference if it is 15% decreased first and then 20% increased

Answer 1

let assumed the number is 100
after 20% increase it will become
100*120/100=120
Now decrease by 15%
100*85/100=85
so net.....120-85=35% ans

Answer 2

Answer:

2 %

Step-by-step explanation:

Hi,

Let the number be X

If we increase the number by 20%, then the number so formed

will become X(1 + 20%)

= X(1 + 1/5)

If we decrease the number by 15%, then the number so formed

will become 6X/5*(1 - 15%)

= 6X/5*(1 - 15/100)

= 6X/5* 17X/20

= 51X/50

Hence the number so formed will be 51X/50

Net Increase in the number = (51X/50 - X)/X*100%

= 1/50*100%

= 2%

Hence, there is a net 2% increase

Suppose , firstly If we decrease the number by 15%, then the

number so formed will become X*(1 - 15%)

= X*(1 - 15/100)

= X* 17X/20

= 17X/20

If we increase the number by 20%, then the number so formed

will become 17X/20(1 + 20%)

= 17X/20(1 + 1/5)

=17X/20*6/5

= 51X/50

Hence the number so formed will be 51X/50. So, there is no

difference , if we interchange the operations of performing

percentages increase or decrease.

Hope, it helps !