Question

Help with equations with two variables

Answer 1

You have two variables, so you need to write two equations. A total of 14 people took the trip, that is, the total of both kinds of tickets that were bought is 14 so you can say: \[c + f = 14\] Then, you have the price of each ticket and the total money spent, so you can say: \[250c + 1150f = 10700\]
And there are your two equations.

Answer 2

You want to know c, so let's get rid of f using the first equation.
\[f = 14 - c\]
Then substitute that into the second:
\[250c + 1150(14 - c) = 10700\]
Solve for c and you have your answer.