15. Let x represent the number of years. The
exponential function is the rent multiplied by 1
16. Sample answer: To determine the total rent paid
after 5 years in a spreadsheet label column A
year, column B rent, and column C annual rent.
A2 = 1, then put the formula = A2+1 in A3 and
copy to the remaining rows. B2 = 2,100, then put
the formula = B2*1.015 in B3 and copy to the
remaining rows. C2 = B2*12 and copy to the
remaining rows. Sum the values in annual rent
for the first 5 years to get the total paid,
$129,837.13. To determine the total paid and
total paid to principal after 5 years in a
spreadsheet, make the Payment Number
column A, Beginning Balance column B, Monthly
Payment column C, Towards Interest column D,
Towards Principal column E, and Ending
Balance column F. The row number is one more
than the payment number. The first entry for
beginning balance is the original principal
amount. The formula for the remaining rows is
the last month’s previous balance, =F2. The
monthly payment formula is,
=(B2*(5.75/1200)*(1+5.75/1200)^(12*20))/((1+5.
75/1200)^(12*20)–1). After the initial row for
monthly payment, the formula that will repeat the
amount for all remaining rows is =$C$2. The
formula to determine interest is, =B2*5.75/1200.
The formula for the amount towards principal is,
=C2–D2. The formula for the ending balance is,
=B2–E2. Sum the columns up to payment 60 for
the 5-year total to get purchase total paid:
17. Sample answer: To determine the total rent paid
after 10 years in a spreadsheet label column A
the formula = B2*1.02 in B3 and copy to the
remaining rows. C2 = B2*12 and copy to the
remaining rows. Sum the values in annual rent
for the first 10 years to get the total paid,
$341,631.30. To determine the total paid and
total paid to principal after 10 years in a
spreadsheet, make the Payment Number
column A, Beginning Balance column B, Monthly
Payment column C, Towards Interest column D,
Towards Principal column E, and Ending
Balance column F. The row number is one more
than the payment number. The first entry for
beginning balance is the original principal
amount. The formula for the remaining rows is
the last month’s previous balance, =F2. The
monthly payment formula is,
=(B2*(6.5/1200)*(1+6.5/1200)^(12*15))/((1+6.5/1
200)^(12*15)–1). After the initial row for monthly
payment, the formula that will repeat the amount
for all remaining rows is =$C$2. The formula to
determine interest is, =B2*6.5/1200. The formula
for the amount towards principal is, =C2–D2.
The formula for the ending balance is, =B2–E2.
Sum the columns up to payment 120 for the
10-year total to get purchase total paid
$313,598.65, total paid toward principal:
$169,935.92.
Assessment
2. 2,000 × 1.01 = 2,200 lb
4. 33,308,000
÷ 9,000 ≈ 3,701 average elephants