Jackson hikes 220.2 meters up a mountain if he is 60% of way up how tall is the mountain

Translate the word phrase into a math expression. 15 fewer than the product of 4 and a number. (pls immediately)

X+y=-4 x-y=2 use elimination with adding and subtraction

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?