Question

If 30% of a number is 18, what is the number ?

Answer 1

Let's rewrite this problem to say 30% of what number is 18.

Well percent means over 100 so we know that 30% means 30/100.

Of means times, what number means x, is means equals,

and 12 means 12.

So we can translate this problem into the following equation below.

30/100 · x = 18

Notice that 30/100 can be reduced to 3/10.

So rewriting our problem we have 3x/10 = 18.

To get rid of the fraction we multiply both sides of the equation by 10 and we have 3x = 180. Dividing both sides by 3 and we find that x = 60.

Now let's check our answer back in the original problem to see if it makes sense. We have 30% of 60 is 18.

Well we know that 100% of 60 would be 60 so 30% of 60 should be a lot less than 60 so 18 seems to make sense.

Answer 2

30/100=18/x.
3/10=18/x.
180=3x.
x=60