Tom had the following scores on math tests: 91, 95, 87 and 83. He has one more test this marking period. What is the lowest grade he can receive if he hopes to raise his average above 90?

94 or 95

Step-by-step explanation:

91 + 95 + 87 + 83 = 356

356/4 =89

average so far is 89

356 + 94 = 450

450/5 = 90

356 + 95 = 451

451/5= 90.2

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.