Your math teacher announces a 50 point quiz tomorrow. There will be a total of 15 questions. Some of the questions will be worth
4 points and some of the questions will be worth 3 points. Use a system to find out how many 4 points questions there will be
1 answer:
Answer:
3x + 4y = 50
x + y = 15
Five 4-point questions
Step-by-step explanation:
Change x + y = 15 to determine what y equal
y = (-x) + 15
Plug it in the original equation using the substitution method
3x + 4(-x + 15) = 50
3x - 4x + 60 = 50
Combine like terms:
-x = -10, two negative signs equals a positive. x = 10
Plug 10 in for x in the equation x + y = 15
10 + y = 15
Subtract 10 from both sides
y = 5
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