Can someone help me please

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.

The track team ran a mile and a quarter during their practice how many kilometers did her team runs?

The height above the ground (in feet) of a ball dropped from the top of a 30-foot-tall building after t seconds is given by the polynomial: ? 16t^2+30 what is the height of the ball after 1/2 second?