I like to break problems down to better understand them. So she ran 6 miles in one week. 6 miles is 1/3 of what she ran in the whole month So there are 2/3 left to fill and that is for 3 weeks
A=12 120% of a =80% of b 120%a = 80%b 120a/100 = 80b/100 Divide through by 100 120a = 80b Divide through by 80 120a/80 = b But a=12 120x 12/80 = b 18 = b b = 18
