If the tide is rising at 1 foot per half hour, how long will it be before Rexy can reach the end of the rope?

Question

Rexy the Tyrannosaur fell overboard while

sailing one day. Fortunately, Rexy is a pretty

good swimmer (in spite of having such short

arms), but even so, she needed to find a way to

get back onto the ship. The ship’s captain threw

a rope down, but it was too short to reach her.

The rope stopped 4 ½ feet above the surface of

the water. Rexy can reach up 2 feet above the

water’s surface.

Answer 1

If you draw this out, and assuming Rexy is directly under the rope, you'll see little Rexy reaching up to the rope. Since his hands reach 2 feet above the water, and the rope is 4.5 feet above the water, there are 2.5 feet between Rexy's hands and the rope (4.5 - 2 = 2.5). SO the water needs to lift him up 2.5 feet.

If the water rises 1 feet per half hour, then you need to figure out how long it takes to go 2.5 feet. you can either do this in your head / logically or use a ratio:

1 foot / 30 mins = 2.5 feet / x minutes

You cross multiply and solve for x... x = 75 minutes.

This makes sense because if 1 foot takes 30 minutes, then 2 feet would take 60 minutes, then going another half foot would take half of what it took to go one foot (15 minutes).

60 + 15 = 75 minutes

Let me know if I can explain any part of this better or if I can help you more in the future!