A frog is at the bottom of a well. The well is 25 feet deep. Each day the frog jumps up 3 feet and falls back 2 feet . How many days will it take the frog to jump out of the well?

Question

Can you show how you got the answer? Please and appreciated!

Answer 1

The explanation above is pretty good. However, it only takes 22 days to get to the top. Here's why:

day 1 jump 3 slide back 2 end at 1 ft. 0 + 3 - 2

day 2 jump 3 slide back 2 end at 2 ft 1 + 3 - 2

day 9 jump 3 side back 2 end at 9 ft 8 + 3 - 2

day 21 jump 3 slide back 2 end at 21 20 + 3 - 2

day 22 jump 3 22 + 3 = 25

He lands at the top, therefore he doesn't need to slide back down any. He is out of the well.

Answer 2

This can be taught with physically jumping/moving, using visuals, through discussion or even through algebraic equations depending on the learning style of the student.

So, let's pretend we are the frog!

If we jump 3 feet up, how far did we go? [3 feet]

If we fall back 2 feet from that point, how far did we go back? [down to 1 foot, 3 feet minus 2 feet equals 1 foot]

Where will we start at tomorrow? [at 1 foot up]

So from there how many feet will we jump up? [3 more feet]

And where will we be at? [4 feet up; 1 foot plus 3 feet is 4 feet]

What happens after we jump up 3 feet? [We fall back 2 feet]

So where will we fall down to? [2 feet; 4 feet minus 2 feet equals 2 feet]

So really how many feet do we keep traveling each day? [only 1 foot per day]

If we are going up 1 foot per day, and we need to go up 25 feet, how many days will it take us to get out of the well? [25 days! Going 1 foot each day.]