Can someone me with 2 math problems?

Three coins are flipped. what is the probability that there will be at least two tails?

Deshawn uses 3/4 of a box of rice to cook dinner the portion he uses weighs 12 ounces right and solve an equation to find the weight of the full box of rice

The function h (t) = -16t squared + 28t + 500 represents the height of a rock t seconds after it's propelled by a slingshot what does h (3.2) represent?