A person standing at the edge of a cliff throws a rock upward from a height of 180ft above ground level with an initial velocity of 64ft/s. Calculate the velocity of the rock when it is exactly 48ft above the person's hand. Separate multiple answers with a comma. (Hint: Use h(t)=−16t2+64t+180 as the position function, where h is in feet, t in seconds. Ignore air resistance.)

Luke started a weight-loss program. the first week, he lost x pounds. the second week, he lost pounds less than times the pounds he lost the first week. the third week, he lost 1 pound more than of the pounds he lost the first week. liam started a weight-loss program when luke did. the first week, he lost 1 pound less than times the pounds luke lost the first week. the second week, he lost 4 pounds less than times the pounds luke lost the first week. the third week, he lost pound more than times the pounds luke lost the first week.