Ian has 12.2 ounce bottle of ketchip. he uses 1/20 of the ketchup every time he has a buffalo burger how many ounces of ketchup are left after ian has eaten 4 buffalo burgers?

If Ian uses 1/20 of the ketchup 4 times, this is equal to 4/20, or .

 can be simplified to , which means we need to work out  of 12.2

is equivalent to 20%, which as a decimal is 0.2

0.2 x 12.2 = 2.44 - however, this is how much he has used, and we need to figure out how much is left.

12.2 - 2.44 = 9.76

So, Ian has 9.76 oz remaining :)