Algebra practice question

Answer: 17

2x + y = (x + y) + x ≤ 10 + x, and x is largest when y is smallest: y = 3, x = 7 gives 17.

Common wrong answers

If you answered 13

13 uses x = 5 and y = 3 without pushing x to its limit.

If you answered 16

16 uses x = 2 and y = 8, which is the minimum end, not the maximum.

If you answered 20

20 uses x = 10, which leaves no room for y ≥ 3.

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…