Answer :
In this problem
6 represent the 100% percentage
Find out the difference (21-6=15)
so
Applying proportion
Find out the percent of increase for the difference of 15
100/6=x/15
solve for x
x=((100/6)*15
x=250%
In this problem
6 represent the 100% percentage
Find out the difference (21-6=15)
so
Applying proportion
Find out the percent of increase for the difference of 15
100/6=x/15
solve for x
x=((100/6)*15
x=250%