Aball pit at a play area is filled with red and yellow balls. of the total number of balls 60 percent are red. if there are 720 red balls, how many balls are in the ball pit?

To solve this we'll put the question in this format: x% of y things = z things

We have the percent so we'll put in 60 for x.
Now the total number of balls will be considered y since we have the number of red balls but not blue ones. so we end up having..

60% of y balls = 720 balls

Of is another word for multiplication, therefore:

60/100*y=720
Solve for y
y=1200

So we have 1200 balls