I have a bag of marbles, where each marble is pink or yellow. The ratio of pink marbles to yellow marbles is 3:5. If there are total of 72 marbles in the bag, how many are pink?

Android4EVER Oct 11, 2018

#1**+2 **

We have 3x+5x=72, 8x=72, x=9 marbles. Since pink is 3x, we have 3*9=27 marbles.

tertre Oct 11, 2018

#2**+1 **

Let the number of pink marbles = p

Let the number of yellow marbles = y

The ratio of pink marbles to yellow marbles is 3:5 . This means...

the number of pink marbles / the number of yellow marbles = 3 / 5

p / y = 3 / 5

There are a total of 72 marbles in the bag. So...

the number of pink marbles + the number of yellow marbles = 72

p + y = 72

y = 72 - p

Now we can use this value of y in the first equation and solve for p .

p / (72 - p) = 3 / 5

Multiply both sides of the equation by 5 .

5p / (72 - p) = 3

Multiply both sides by (72 - p)

5p = 3(72 - p)

5p = 216 - 3p

Add 3p to both sides.

8p = 216

Divide both sides by 8 .

p = 27

the number of pink marbles = 27

hectictar Oct 11, 2018