Shari and ana are playing games at an arcade, shari has
$37.50 and is playing $0.50 games. ana has $12.75 and
is playing $0.75 games, sandor wants to know when
shari and ana will have the same amount of money
remaining, so he wrote and solved this equation,
let x number of games played,
equation: 37.50 -5x42.75 - 75x
step 1
37.50 -1.25x 34
step 2: -1,25x5,25
step 3 -4.2 x
sandor knows his answer is incorrect because a
negative number of games cannot be played. what was
sandor's mistake?
the variable x should represent the amount of
money left
the equation should have sums on both sides.
in step 1, he should have added.75x to both sides,
in step 3, he should have added 1.25x to both sides.

In step 1, he should have added .75x to both sides.

c) in step 1, he should have added .75x to both sides

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.