Yvonne ran up 1/4 of the total stairs. Afterwards, she walked the REST of the stairs, which is said to be 9 STAIRS. HOW MANY flights of stairs IN TOTAL did she run up?
When she ran the REST of the stairs, it meant she ran the other 3/4 of stairs because: 1 - 1/4 = 3/4
To add someting, that means that the 9 stairs is 3/4 of the total stairs, so lets fins the total stairs using this information: 9 ÷ 3/4 = 12