A taxi company charges f
cents for the first mile of the taxi ride and m
cents for each additional mile. How much does the company charge for a 10-mile taxi ride?
(1) The company charges $0.90 for a 2-mile ride.
(2) The company charges $1.20 for a 4-mile ride.
We are given: f + 9*m = Total Cost, by the stem.
1) Tells us that f + m = 0.9, given that we have three unknowns but two equations, this is not enough.
2) This gives us f + 3m = 1.2, (which btw clearly is NOT the same info as in 1), so we have 3 unknowns and 2 equations, insufficient.
1 + 2. 3 equations and 3 unknowns, sufficient. We can add 1 and 2 together to solve for total cost, and we can add the info from the stem with one of the statements in 1 or 2 to solve for the third. C is our answer.