Question

a company machine makes 24 copies per minute. how many copies does it makes in 4 minutes and 45 seconds?

Answer 1

Yikes! Don't worry. This problem isn't as hard as it looks.

Just be sure to watch your units, and make a proportion.

We know how many seconds are in a minute, and we know how many copies that this uh, company machine, can make in 60 seconds; 24 copies, to be exact. In four minutes, you have 60+60+60+60 = 240 seconds. Add the other 45 seconds and you see we've got 285 total seconds. So now that our units are all equal, we make our proportion.

"24 copies is to 60 seconds as an UNKNOWN amount of copies is to 285 seconds." That's the proportion. In math-ese, this says: (24/60) / (x/285)

Write that out, and cross multiply to get the equation: 60x = (24)(285)

x = 114, so we know that in 4 minutes and 45 seconds, this machine can make 114 copies.