Quick Math Question

1 / (1/9 - 1/11)

common way to pose the same question is a monkey climbing up a pole climbs at 5 ft/hr and then falls 3 ft at the end of each hour - how long to climb a pole of x height.

mistake is to assume net 2ft/hour, but you need to bear in mind that once you reach the top, you don't fall

what job is this for? S&T?

In 1 hour, 1/9 of the tank's volume is filled (V/9) and in 1 hour, 1/11 of the tank's volume is drained (V/11), so effectively, in 1 hour V/9 - V /11 = 2V/99 of the tank is filled. So total time taken is volume/rate = V/(2V/99) = 99/2 hours, or 1/(1/9 - 1/11) as pussinboots said

I loathe this sort of SAT questions... I must have been good at this when I was at HS but now it's simply unbearable. The solution above is very clear but I wouldn't have come up with it on my own.

a coworker asked me and i wanted to confirm my 49.5 before giving it to him. thanks for the help guys - though i had no idea why he had this question, wouldn't tell me :/ -product control

im almost certain this is a problem off of the 11th edition from OG GMAT.