Anumber is (1\7) of another number. the difference of the numbers is 18. (assume that you are subtracting the smaller number from the larger number.) find the numbers.

Start by writing an equation

x - 1/7x = 18

since there is no number in front of the first x it is an implied 1. In order to subtract we need an equivalent fraction with a common denominator so we change 1 to 7/7.

Now we can subtract
7/7x - 1/7x = 18
6/7x = 18

divide each side by 6/7 (multiply 18 × the reciprocal)

x = 18/1 × 7/6

x = 126/6

x = 21

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