10 people are going canoeing/tubing. some people will tube, some will canoe. tubes are $7 each. canoes are $11 each. tubes hold one person. canoes hold three. if you want to spend exactly $50, how many canoes and tubes can you buy?

i know this is a linear combination question. the equation for the cost i figured is 7t + 11c = 50 (t for tubes, c for canoes)

For the other part of the combination, you would say c=3t, because if a tube only holds one person, and a canoe holds three, then the amount of people in three tubes is equal to the number of people in one canoe. Do you get it?