Question

Susan is creating a solution. A formula for the solution calls for 7/10 mL of water. Susan wants to make 2/7 less of the solution than the formula creates.

How much water should Susan use?

Express your answer as a fraction in simplest form.

[ ? ML ]

Answer 1

First find the greatest common denominator of 10 and 7

Answer 2

@Thebadyboy What is 10 * 7?

Answer 3

70

Answer 4

Greatest common denominator is the common number and both 7 and 10 go into in this case it would be 70 right!

Answer 5

So now 7/10 is the same as 49/70 since all you have to do is multiply 7 by both sides and you get 49/70. Same with 2/7 multiply both sides by 10 and you will get?

Answer 6

yes

Answer 7

20/70

Answer 8

Exactly! So now grab both of the fractions and subtract them...
So \[\frac{ 49 }{ 70 }-\frac{ 20 }{ 70 } =?\]

Answer 9

What do you get?

Answer 10

@Thebadyboy what is \[\frac{ 49 }{ 70 }-\frac{ 20 }{70 } = ?\]

Answer 11

um 29/70

Answer 12

YES^^^^ That's the answer!!!!

Answer 13

and its already in simplest form.

Answer 14

thx

Answer 15

No problem.

Answer 16

I don't buy it.

If a cookie recipe calls for a stick of butter to make a batch of cookies, then if I want to make half a batch of cookies, I would cut the amount of all the ingredients in half. So that stick of butter becomes 1/2 a stick of butter.

Mathematically it would look like this: 1/2 * 1 = 1/2

Since she wants to reduce the amount of solution by 2/7, she needs 5/7 of the water called for in the formula.