Posted by Chayo on .
Round your answer to the nearest tenth of a percent.
By switching service providers, a family's telephone bill decreased from about $50 a month to about $47. What was the percent of decrease?

MATH 
Ms. Sue,
50  47 = 3
3/50 = 0.06 = 6.0% 
MATH 
Chayo,
So what you should do first is always subract then divide what ever answer you got by 50 for instance in this problem it was decreased from 50. So we are trying to figure out what was the decrease in 47. right

MATH 
Ms. Sue,
Right.

MATH 
Chayo,
Is it always going to be subtraction then division or it all depends on the question what it's asking you for.

MATH 
Marth,
When finding a percentage change, you will need to divide the magnitude of increase by the prior value.
The magnitude of increase may be given, or you may have to find it, by subtracting 5047 in this case.
The prior value is given as 50.
Then, divide to find the percent change.