50 % of blank = 21 plz I need help with that question

Ben bowled 124 and 188 in his first two games. what must he bowl in his third game to have an average of at least 160?

Kapil needed to buy a long wooden beam. he went to two sawmills that each charge an initial fee plus an additional fee for each meter of wood. the following equation gives the price (in dollars) of a wooden beam from the first sawmill as a function of its length (in meters). p = 5+20xp=5+20x

Which simplifys to a+ b? a-(1-b)+1 -(1-a)-b+1 (a--1) -1)+1