Officials begin to release water from a full man-made lake at a rate that would empty the lake in 4 weeks, but a river that can fill the lake in 15 weeks is replenishing the lake at the same time. how many weeks does it take to empty the lake? express your answer as a fraction reduced to lowest terms, if needed.

Agroup of students were investigating the force of gravity. they began by dropping a foam ball from a height of 3 meters into a bucket of sand. the ball hit the sand in 0.306 seconds. they dropped additional balls of approximately the same diameter, but of different masses. here is the data they collected. based on this experiment and the collected data, what would their conclusion be?