If 2/3 of a cup of juice gives you 120% of your daily value of vitamin C, what percent of your daily vaulue of vitamin C will you get in 1/2 cup of the juice?

Question

What would the equation be? I got 2/3 times 120x = 1/2

Answer 1

120/2=60, So a full cup of juice should give you 180% of your daily value, now just divide 180/2=90. So 1/2 a cup of juice = 90% of your daily value of vitamin C.

Answer 2

2/3 times 120x = 1/2
is not the right equation. The proper proportion is
120 ÷ 2/3 = x ÷ 1/2

Answer 3

That’s not an equation. What would the equation be?

Answer 4

any set of terms separated by an = sign is an equation.
If you clear all the fraction from my equation, you would get
60% = 2/3 x
And you would still arrive at the solution of x=90%

Answer 5

I have 3 blocks and I shade 2/3 of those blocks leaving me with 1/3. Each of the blocks is 40 since 40+40+40 = 120. So 120/40 = 3.
I still don’t know why you divided 120 by 2

Answer 6

I didn't divide it by 2 -- I multiplied it by 1/2

a proportion is an equation of the form

a/b = c/d

It means that the ratio of a to b is the same as the ratio of c to d.
We have a ratio relating % to cups, namely
120% to 2/3 cup
now we want the % in 1/2 cup. These will be in the same ratio as the first comparison: 120% to 1/2 cup

So, you set up the proportion as I gave it, so you can solve for x.

120 ÷ 2/3 = x ÷ 1/2
120 * 1/2 = x * 2/3
60 = 2/3 x
x = 60 * 3/2 = 90

I guess it's time to put away your fraction strips or whatever tool you have been using, and start learning the algebra behind it. Those math manipulatives can be very helpful in the beginning, but they can only take you so far.

Answer 7

We are supposed to use the strips!

Answer 8

(1/2)/(2/3) * 120% = 1/2*3/2 * 120% = 3/4 * 120% = 90%.