abbyen1
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# A science test, which is worth 100 points, consists of 24 questions. Each question is worth either 3 points or 5 points. If x is the number of 3-point questions and y is the number of 5-point questions, the system shown represents this situation. x + y = 24 3x + 5y = 100

$\left \{ {{x+y=24} \atop {3x+5y=100}} \right.$ ⇒$\left \{ {{x=24-y} \atop {3*(24-y)+5y=100}} \right.$⇒ $\left \{ {{x=10} \atop {y=14}} \right.$ The number of 3-point questions is 10 and of 5-point questions is 14.