Fractional equations

Question

The sum of the reciprocal of a number and one ninth is one fifth. What is the number? 

Answer 1

1/x + 1/9 = 1/5

1/5 - 1/9 = 1/x

 

First you have to make the problem doable. Find the Greatest Common Factor (GCF) by multiplying the denominators.

5*9=45

Then multiply the numerators by the same number you did to the denominators.

1/5 multiplied by 9 becomes 9/45, because 1*9=9 and 5*9=45.

1/9 multiplied by 5 becomes 5/45, because 1*5=5 and 9*5=45.

9/45 - 5/45 = 4/45

4/45 divided by 4 becomes 1/11.25, because 4/4=1 and 45/4=11.25

1/11.25 is the reciprocal of the number. Flip it to get the original. 11.25/1=11.25

 

x = 11.25