Please help to solving two tasks with MathCad

Hello,

Please help to solving two tasks with MathCad?

1) Water tank, the base of which runs through the water, is filled with 50 cm heights. It is known that the leakage rate is proportional to the square root of the water column. During hour, the water level dropped 9 cm. How long is the water level dropped to 40 cm and when the tank is empty?

2)During the test, the stone was placed at a temperature of 60 ° in the current form at 20 degrees in water. The stone was cooled to 40 ° C for 2 minutes. Find the temperature of the stone for 5 and 10 minutes after.

Graphs is needed

Please feedback

Br.V