Each of 36 students at a school play bought either a cup of orange juice or a sandwich. A cup of orange juice costs $1 and a sandwich costs $3. The total amount collected was $76. How many students bought orange juice, and how many bought a sandwich? Let x represent the number of students who bought a cup of orange juice and y represent the number of students who bought a sandwich. Then the problem can be represented by this system of equations: 1. Explain what you should do with the two equations to eliminate one of the variables. (2 points)

2. Find the value of y. (3 points)

3. Find the value of x. (2 points)

4. Interpret the solution and check the values in the system. (3 points)

Step-by-step explanation:

1. We can write the equation like this:

x + y*3 = 76

x + y = 36

2.This means that two "y" is 40, since the difference between x + y + y + y and x + y is 40. If two "y" is 40, then one must be 20.

3. If "y" is 20, then x must be 16, since 36 - 20 is 16.

4. Just interpret the solution yourself.

answer: c, the green line

step-by-step explanation:

there is no black line, eliminate b.

simple interest implies periodic payments, but the red line shows no payments, eliminate d.

simple interest has equal payments. if paid say every day, the graph is about a straight line (actually a stairstep).

the yellow line is not straight, eliminate a.

check: the green line is straight, answer is c.

simple interest with positive interest rate gives a straight line sloping up to the right. green line:

g(t) = $100 + ($200-$100) ÷ (20 years) × (t years)

= $100 + (4%/year) × ($100)(t years)

incidentally, the yellow line curving upward represents continuously compounded interest

y = $100 × 2^(t years / (14 assuming the yellow line hits $200 at 14 years. 2^0 is 1, so y(0) = $100; 2^(14/14) is 2, so y(14) = $200.