Answer:
  The test contains 10 three-point questions and 14 five-point questions.
Step-by-step explanation:
3x + 5y = 100, so:
x  - number of 3-point questions Â
y - number of 5-point questions Â
x + y = 24   ⇒  y = 24 - x
3x + 5y = 100
3x + 5(24-x) = 100
3x + 120 - 5x = 100
-2x = -20
 x = 10
y = 24 - 10 = 14