OnlineMSchool
Study of mathematics online.
Study math with us and make sure that "Mathematics is easy!"

Find the number A if known number B which greater (less) than A by P percent.

Formula for calculating the number A if known number B which is greater than A by P percent.

If we have the number B, which is greater then A by P percent and need to find A, then

A =  B · 100%
100% + P

Formula for calculating the number A if known number B which is less than A by P percent.

If we have the number B, which is less then A by P percent and need to find A, then

A =  B · 100%
100% - P

For the derivation of this equation using the method of solving problems with percentage

If "Part" more then "All" by P percent then

All   -   100%
Part   -   100% + P

have proportion

"All" = 100%   =>   "All" = "Part" · 100%
"Part"100% + P100% + P

If "Part" less then "All" by P percent then

All   -   100%
Part   -   100% - P

have proportion

"All" = 100%   =>   "All" = "Part" · 100%
"Part"100% - P100% - P

Examples of calculating number A if known number B which greater (less) than A by P percent.

Example 1.
Find the number if 66 greater then this number by 10%.

Solution.

66 · 100% = 60
100% + 10%

Answer: 60.



Example 2.
Find the number if 63 less then this number by 10%.

Solution.

63 · 100% = 70
100% - 10%

Answer: 70.



Example 3.
Client put money on deposit in the bank at 12% per annum, a year later the he have $ 33,600. How much money client put on the deposit?

Solution.

33,600 · 100% = 30,000
100% + 12%

Answer: client put on the deposit $ 30,000.

In the study of percent to you also will be helpful:

Add the comment

0