CPM Homework Help : A2C Problem 2-39

Lona received a stamp collection from her grandmother. The collection is in a leather book and currently has 120 stamps. Lona joined a stamp club, which sends her 12 new stamps each month. The stamp book holds a maximum of 500 stamps. Homework Help ✎
1. Complete the table below.
  Month
  Stamps
  0
  120
  1
  132
  2
  3
  4
  5
2. How many stamps will Lona have after one year?
3. Write an equation to represent the total number of stamps that Lona has in her collection after n months. Let the total be represented by t(n).
4. Solve your equation for n when t(n) = 500. Will Lona be able to fill her book exactly with no stamps remaining? How do you know? When will the book be filled?

Month	Stamps
0	120
1	132
2
3
4
5

Hint (a):

Continue adding 12 to find months 2-5.

Table (a):

Answer (a):

Hint (b):

See part (a). (Continue until month twelve.)

Hint (c):

Remember that the initial amount was 120 stamps and the rate is 12 stamps per month.

Answer (c):

Use these values to make an equation.

t(n) = 120 +12n

Step 1(d):

Substitute 500 for t(n).

500 = 120 + 12n

Step 2(d):

Solve for n.

$\textit{n}=31\frac{2}{3}$

Answer (d):

Lona will not be able to fill her book exactly, with no leftover stamps, because when the equation is solved for n, the result is a mixed number. It will be filled in 32 months.