how do you divide 7/15 by 3/5

Question

how do you figure out 7/15 by 3/5?

Answer 1

Remember that dividing is equivalent to multiplying by the inverse of a number.

For instance, 10/5 = 2 and 10 * 1/5 = 2.

In this case (and all cases with whole numbers), changing inverting the denominator and multiplying is the same as dividing.

 

For your question:

- 7/15 / 3/5 is equivalent to 7/15 * 5/3

- which is equivalent to (7 * 5 ) / (15 * 3)

- which is equivalent to (7 * 5) / (5 * 3 * 3)

- Cancelling out the two fives (5) on either side of the fraction leaves us with 7 / (3 * 3) or 7/9 (or .77 repeating )

To check with a calculator - try 7 / 15 / 0.6.  You will get 0.77 repeating  as well - 7/9.

Hope that works.

 

Cheers Ken