A frog fell into 30 metres deep well and tries to get out, it goes 3 metres up and fall 2 metres every day. Calculate the no. of days it take to get out.

Options

A. 30 days
B. 28 days
C. 15 days
D. 24 days

Answer

B

Explanation

According to the question
`1^(st)` day it rises 1 m
`2^(nd)` day it rises 2 m i.e. (1 + 1) m
3rd day it rises 3 m i.e. (2 + 1) m
`27^(th)` day it rises 27 m i.e. (26 +1) m
But on `28^(th)` day by climbing 3 metres it gets out, no chance for slip or fall again i.e. (27 + 3) m = 30 m.
Therefore, in 28 days it will get out of well.