Question

a gym is selling monthly membership for $30 each and reusable water bottles for $7 each. the gym needs to make $1050 by the end of the month

Answer 1

x = gym memberships, and y = bottles of water
30x + 7y = 1050.....when x = 28
30(28) + 7y = 1050
840 + 7y = 1050
7y = 1050 - 840
7y = 210
y = 210/7
y = 30....so he would have to sell 30 water bottles