In the formula, u is the amount of unearned interest (money saved) when a loan scheduled to
run for n payments is paid off k payments ahead of schedule. The total scheduled finance
charge is ƒ. Use the formula for the rule of 78 to work Exercises 37–40.
37.Sondra Braeseker bought a new car and agreed to pay it off in 36 monthly payments. The
total finance charge was $700. Find the unearned interest if she paid the loan off 4 pay-
ments ahead of schedule.
38.Donnell Boles bought a truck and agreed to pay it off in 36 monthly payments. The total
finance charge on the loan was $600. With 12 payments remaining, he decided to pay the
loan in full. Find the amount of unearned interest.
39.The finance charge on a loan taken out by Kha Le is $380.50. If 24 equal monthly install-
ments were needed to repay the loan, and the loan is paid in full with 8 months remaining,
find the amount of unearned interest.
40.Maky Manchola is scheduled to repay a loan in 24 equal monthly installments. The total
finance charge on the loan is $450. With 9 payments remaining, he decides to repay the
loan in full. Find the amount of unearned interest.
In baseball, winning percentage ( Pct.) is commonly expressed as a decimal rounded to the
nearest thousandth. To find the winning percentage of a team, divide the number of wins
by the total number of games played 1 W+L 2.
1 W 2
SECTION 2.2 Formulas and Percent 65
41.The final 2009 standings of the Eastern
Division of the American League are
shown in the table. Find the winning
percentage of each team.
(a)Boston (b)Tampa Bay
(c) Toronto (d)Baltimore
42.Repeat Exercise 41for the following
standings for the Eastern Division of the
National League.
(a)Philadelphia (b)Atlanta
(c) New York Mets (d)WashingtonSource: World Almanac and Book of Facts.W L Pct.
New York Yankees 103 59 .636
Boston 95 67
Tampa Bay 84 78
Toronto 75 87Baltimore (^6498) Source: World Almanac and Book of Facts.
W L Pct.
Philadelphia 93 69
Florida 87 75 .537
Atlanta 86 76
New York Mets 70 92
Washington 59 103
As mentioned in the chapter introduction, 114.9million U.S. households owned at least one TV
set in 2009. (Source: Nielsen Media Research.) Use this information to work Exercises 43– 46.
Round answers to the nearest percent in Exercises 43 – 44, and to the nearest tenth million in
Exercises 45 – 46. See Example 6.
43.About 62.0 million U.S. households owned 3
or more TV sets in 2009. What percent of
those owning at least one TV set was this?
44.About 102.2 million households that owned at
least one TV set in 2009 had a DVD player.
What percent of those owning at least one TV
set had a DVD player?
45.Of the households owning at least one TV set in 2009, 88% received basic cable. How
many households received basic cable?
46.Of the households owning at least one TV set in 2009, 35% received premium cable. How
many households received premium cable?