AlgebraVery hardDistance from a slope and a target value
Algebra practice question
The function d(t) = −2t + 20 gives the distance, in kilometres, between a walker and her home t hours after she sets off toward it. How many hours after setting off will she be 8 kilometres from home?
Answer: 6
−2t + 20 = 8 gives 2t = 12, so t = 6.
Common wrong answers
- If you answered 4
- 4 solves 2t + 20 = 28, with the slope's sign wrong.
- If you answered 10
- 10 is when she reaches home.
- If you answered 14
- 14 solves −2t + 20 = −8.
More Algebra questions
- Very hard
For what value of c does the system 3x − 2y = 8 and 9x + cy = 5 have no solution? - Very hard
In the system 5x + 4y = 32 and 3x − 2y = 6, what is the value of 8x + 2y? - Very hard
The solution set of the inequality |ax − b| ≤ 6, where a and b are constants and a > 0, is 3 ≤ x ≤ 9. What is … - Very hard
The function f is linear, and for every value of x, f(x + 2) − f(x) = 6. If f(5) = 4, what is the value of f(0… - Very hard
In the system of equations 2x + 3y = 12 and 5x − 2y = k, where k is a constant, the solution (x, y) satisfies … - Very hard
In the xy-plane, the system of equations kx + 6y = 12 and 2x + (k − 1)y = 6, where k is a constant, has infini…
Not affiliated with the College Board. SAT is a trademark of the College Board.