help me solve my confusion if a number x is 10% less than another number y and y

Question

if a number x is 10% less than another number y and y is 10%more than 125 then x is equal to

please understand my confusion read carefully i know the solution

 

y=125*10/100+125                       y-y*10/100=125

y=137.50                                      0.90y=125

                                                    y=138.89

 

both are equation but have different answers this example is easy so i can understand because 125 is no so i can have only 125 of 10% therefore 1 is correct. but how to tackle complex problems

 

same for second equation

now x is 10% less means 10% of x or 10%of another number y how to determine.so please teach how to determine that any percent number of that number or other number

 

 

Answer 1

x = (90%)y         Same as 10% less.

y = (110%)125    Same as 10% more

 

y = 137.5

x = (90%)(137.5)

x = 0.9(137.5)

x = 123.75

Answer 2

Percent can be expressed as a % (for example 75%) or a fraction (75/100 = 3/4) or a decimal (0.75) as needed in the problem.  The word "of" usually means multiply.

 

KEY:  The important information that most people miss is that the original value is what you are taking a percentage of.  For example, "x is 10% less than y" means x = y - (10%)y = (9/10)y = 0.9y.  The original value is y.

 

"y is 10% more than 125" means that 125 is the original value.  10% more is (110%)(125)= (11/10)(125) = (1.10)(125) = 137.5.

 

So, if x=(0.9)y

        x = (0.9)(137.5)

        x = 123.75

 

This is interesting:  If you work hard and get a 10% raise this year, but next year you take a job for 10% less, your final salary will not be equal to your original salary (because of different original values for calculating the percent).