Math Problem Statement

Priya is stacking boxes of height 2.25 cm and starts with 3 boxes. Complete the table of the stack height h(n) after n boxes are added. For another problem, a piece of paper starts with an area of 54 square inches and each person cuts 1/3 of the remaining paper. Complete the area table A(n) after n cuts and define a reasonable domain.

Solution

Problem Breakdown and Solutions:

Question 2

  • Given: Priya is stacking boxes. Each box is 2.25 cm tall. She starts with 3 boxes.
  • a) Complete the table for h(n)h(n), the height of the stack after nn additional boxes are added.

We calculate h(n)h(n): h(n)=Initial height with 3 boxes+Height of added boxesh(n) = \text{Initial height with 3 boxes} + \text{Height of added boxes} The initial height with 3 boxes: 3×2.25=6.75cm.3 \times 2.25 = 6.75 \, \text{cm.} For each additional box: Height added=n×2.25.\text{Height added} = n \times 2.25. Thus, the function becomes: h(n)=6.75+2.25n.h(n) = 6.75 + 2.25n.

nnh(n)h(n) (cm)
06.75
16.75 + 2.25 = 9.00
26.75 + 4.50 = 11.25
36.75 + 6.75 = 13.50
  • b) Does h(8)h(8) make sense? To calculate h(8)h(8): h(8)=6.75+2.25×8=6.75+18=24.75cm.h(8) = 6.75 + 2.25 \times 8 = 6.75 + 18 = 24.75 \, \text{cm.} This makes sense because the formula is valid for any non-negative integer nn and represents the height after stacking boxes.

Question 3

  • Given: A piece of paper starts with an area of 54 square inches. Each person cuts 13\frac{1}{3} of the remaining area.

  • a) Complete the table for A(n)A(n), the area after nn cuts.

The recursive pattern is: A(0)=54,A(0) = 54, A(n)=23A(n1).A(n) = \frac{2}{3} A(n-1). Calculate: A(1)=23×54=36,A(1) = \frac{2}{3} \times 54 = 36, A(2)=23×36=24,A(2) = \frac{2}{3} \times 36 = 24, A(3)=23×24=16.A(3) = \frac{2}{3} \times 24 = 16.

nnA(n)A(n) (sq in)
054
136
224
316
  • b) Define A(n)A(n) for the nn-th term: The explicit formula for A(n)A(n): A(n)=54×(23)n.A(n) = 54 \times \left(\frac{2}{3}\right)^n.

  • c) Reasonable domain: Since the cutting process continues indefinitely, nn can be any non-negative integer: Domain: nZ0.\text{Domain: } n \in \mathbb{Z}_{\geq 0}. This makes sense because nn represents the number of cuts, and it cannot be negative.


Next Steps

Let me know if you'd like further clarifications!
Here are 5 related questions to extend learning:

  1. How would the formula for h(n)h(n) change if the initial stack had 5 boxes?
  2. What happens to A(n)A(n) as nn \to \infty?
  3. How do recursive and explicit formulas differ in practical applications?
  4. Can h(n)h(n) or A(n)A(n) have real (non-integer) values for nn?
  5. How would the stacking formula change if each box had a different height?

Tip: Always look for patterns in repetitive calculations to derive general formulas quickly!

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Math Problem Analysis

Mathematical Concepts

Linear functions
Recursive sequences
Exponential decay
Domain and range in functions

Formulas

h(n) = Initial height + Height of additional boxes
h(n) = 6.75 + 2.25n
A(n) = A(0) * (2/3)^n
A(n) = Recursive formula: A(n) = (2/3) * A(n-1)

Theorems

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Suitable Grade Level

Grades 6-8