80% means 80/100 = 0.80
220/0.80
= 275
======Check.
220/275 * 100
= 80%
======
80% of a number is 220.What is that number? Show work.
Make proportion
220/x = 80/100
80x = 22000
x = 22000/80
x = 275
General formula for this type of word problem:
If (#%) of (a number) is (answer), then of means * and is means =
the formula is (#%) * (a number) = (answer)
or 80% is equivalent to .8, so the equation is (.8)*(x) = 220 which when solved gives x = 275