Tommy wished he practiced more before his violin concert. If he had practiced 1 1/2 more hours one week, he would have averaged 8 hours per week for the four week prior to his concert. How many hours did he practice in the 4 weeks?

30.5 hours

Step-by-step explanation:

If he were to average 8 hours PER week for 4 weeks, his total sum would have been:

8 * 4 = 32 hours

But he fell short of it. By how much?

By hours!

So, he practiced 1  1/2 hours LESS THAN 32 hours, so his practice time is:

So, he practiced 30.5 hours in the 4 weeks

-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.