Question

a froge tries to come out of a dried well 9 m deep with slippery walls. every time the froge jumps 60 cm, he slides back by 30 cm. how many jumps will the frog have to take to come out of the well?

Answer 1

$let \: no. \: of \: jump = x \\ distence \: in \: one \: jump = 60 - 30 = 30cm \\ 30(x - 1) + 60 = 900 \\ 30x - 30 + 60 = 900 \\ 30x + 30 = 900 \\ 30x = 900 - 30 \\ 30x = 870 \\ x = \frac{870}{30} = 29$