Question

isabell is mixing red paint with blue paint to make purple paint.she adds 3/10 of a fluid ounce of red to 11/15 of a fluid ounce of blue to make 1 1/30 fluid ounces of blue to make 1 1/30 of purple.how many fluid ounces of red will she need to make 3 fluid ounces of purple paint

Answer 1

We will need 27/31 of an ounce of red

Explanation:

3 /10 red + 11 /15 blue makes 1 1/30 purple

Get a common denominator of 30

3/10 * 3/3 = 9/30 red

11/15 *2/2 = 22/ 30 blue

1 1/30 = 31/30 purple

So the ratio of red to purple is

9/30

-------- = 9/ 31

31/30

Keeping this ratio, we want 3 ounces purple

9 red x red

-------- = --------------

31 purple 3 purple

Using cross products,

9*3 = 31 *x

27 = 31x

Divide each side by 31

27/31 = x

We will need 27/31 of an ounce of red