1. To collect data on the signal strengths in a neighborhood, Briana must drive from house to house and take readings. She has a graduate student, Henry, to assist her. Briana figures it would take her 12 hours to complete the task working alone, and that it would take Henry 18 hours if he completed the task by himself. How long will it take Briana and Henry to complete the task together?

a 5.6 hours

b 7.2 hours

c 6.7 hours

d 4.5 hours

2. An initial deposit of $3,000 is put into an account that earns 6% interest, compounded annually. Each year, an additional deposit of $3,000 is added to the account. Assuming no withdrawals or other deposits are made and that the interest rate is fixed, the balance of the account (rounded to the nearest dollar) after the seventh deposit is __________.

a $25,095

b $25,182

c $24,208

d $24,401

3. Suppose $18,000 is deposited into an account paying 8.5% interest, compounded continuously. How much money is in the account after 10 years if no withdrawals or additional deposits are made?

a $43,878.62

b $42,113.64

c $43,278.39

d $44,7782.30

4. You want to buy a new car. The bank offers you a loan for $30,000 at a 3% interest rate. You are willing to pay $4,500 in interest over the life of the loan. In how many years must you pay off the loan to meet your goal?

a 6 years

b 3 years

c 7 years

d 5 years