Solution: Find the amount of salt in the tank at the end of 30 minutes

Solution: How much salt is in the tank at the end of one hour?

Solution: What is the velocity of the object one second after it falls?

Solution: How long will it take to cool from 100° to 50°?

Solution: Find the equation of the family of orthogonal trajectories of the system of parabolas y^2=2x+C

Solution: What is the percentage lost of Radium in 100 years?

Solution: If population of a country doubles in 50 years, how many years will it be five times as much?

Solution: How many mg of Radium will be left after 100 years?

Solution: Determine the differential equation of the family of circles with center on the y-axis

Solution: Determine the differential equation of the family of lines passing through (h, k)