Question

A baker has 3/4 a pound of sugar 2/5 of a pound of cinnamon and 4/5 of a pound of flour. She uses 1/5 of a pound of each. How much sugar, cinnamon, and flour does she have left?

Answer 1

First, make all the denominators the same.

In this case, all the denominators are of the value of either 4 or 5. So, now what is the biggest number we can multiply by, using four AND five.

Answer is 20 because 5*4 is 20 and 4*5 is 20.

So now for all the ingredients, we have to :

-multiply the whole fraction by 4 if the denominator is 5

- Multiply the whole fraction by 5 if the denominator is 4

So for sugar, you would do 3/4 ( times 3 by 5, times 4 by 5)

Which is 15/20

For cinnamon, you would do 2/5 ( times 2 by 4, times 5 by 4)

Which is 8/20

For flour, you would do 4/5 ( times 4 by 4, times 5 by 4)

Which is 16/20

But, for your problem, you need to work out how much the baker has left over after using 1/5 of pound of all the ingredients. So, you would do 1/5 ( times 1 by 4, times 5 by 4)

Which is 4/20

Now, we can subtract it by the ingredients For sugar:

15/20 - 4/20

Now the baker has 11/20 pound of sugar

For cinnamon:

8/20 - 4/20

Now the baker has 4/20 pound of cinnamon ( simplified fraction is 1/5)

For flour

16/20 - 4/20

Now the baker has 12/20 pound of flour ( simplified fraction is 3/5)

Hope this helps;)