A pot of soup, currently 13 Celsius above room temperature, is left out to cool. If that temperature difference decreases by 10% per minute, then what will the difference be in 18 minutes

Aswimming pool has an input pump for filling the pool and an output pump for emptying the pool. the input pump can fill the pool in 3 hours, and the output pump can drain the pool in 5 hours. as you go to bed, the pool is full, but a neighbor’s kid turns on the output pump. at midnight, you awake to find the pool half empty. immediately, you turn on the input pump, but you are sleepy and forget to turn off the output pump. at what time will the pool become full?

Which graph depicts the path of a projectile

What is the point of inflection for the function f(x)=2cos4x on the interval (0, pi/2)