The tortoise fell to a depth of 17 meters in the morning. Every day it rises by 5 meters during the day and slides down by 2 meters at night. How many days does a tortoise come out of the depths?​

x-days

z-during the day times

y-during the night times

Logical the day includes two parts. Day and night. And they have the same quantity. If tortoise during the day rises 5 meters every day, it will be 5z,and if tortoise slides down during the night it will be 2y.

5z-2y=17

Answer is:4.5

Because if tortoise reaches the top it will come out. Then if we will put 4.5 into the equation. It will not fit. I think it's logical task rather than math task