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Page 133: Matha Pachchi & Deep Dive

April 10, 2024
2 min read

Matha Pachchi: Akshi vs Toshi

Scenario:

  • Akshi’s Track (Outer): Rectangle 70 m×40 m70\text{ m} \times 40\text{ m}.
  • Toshi’s Track (Inner): Rectangle 60 m×30 m60\text{ m} \times 30\text{ m}.

1. Total distance Akshi covered in 5 rounds:

Perimeter (Akshi)=2×(70+40)=2×110=220 mDistance=5×220=1100 m\begin{aligned} \text{Perimeter (Akshi)} &= 2 \times (70 + 40) = 2 \times 110 = 220\text{ m} \\ \text{Distance} &= 5 \times 220 = 1100\text{ m} \end{aligned}

2. Total distance Toshi covered in 7 rounds:

Perimeter (Toshi)=2×(60+30)=2×90=180 mDistance=7×180=1260 m\begin{aligned} \text{Perimeter (Toshi)} &= 2 \times (60 + 30) = 2 \times 90 = 180\text{ m} \\ \text{Distance} &= 7 \times 180 = 1260\text{ m} \end{aligned}

Conclusion: Toshi ran a longer distance (1260>11001260 > 1100).

Deep Dive (Page 134)

Problem: Two square tracks, Inner (100m side) and Outer (150m side). Common finish line. Race length is 350m. Where should they start?

Analysis:

  • Race distance needed: 350 m.
  • The finish line is in the middle of a side. Let’s analyze the path backwards from the finish line.
  • Inner Runner (A):
    • Side length = 100 m.
    • Path to finish: Half side (50m) + Full Side (100m) + Full Side (100m) + Full Side (100m) = 350m.
    • This means runner A starts exactly at the finish line (completes exactly 1 round minus 50m? No, 350=3.5×100350 = 3.5 \times 100).
    • Actually, let’s look at the solution provided: “From point A to flag: 100+100+100+50=350100+100+100+50 = 350”. This implies starting at a corner or specific point.
  • Outer Runner (B):
    • Side length = 150 m.
    • Path: 75 (half side)+150+12575 \text{ (half side)} + 150 + 125?
    • Solution says: 125+150+75=350125 + 150 + 75 = 350.
    • 7575 is the final stretch (half side). 150150 is one full side. 125125 is the start of the side (15025150 - 25?).
    • Actually, 125+150+75=350125 + 150 + 75 = 350. This means they run 1 full side (150150), one half side (7575) to finish, and start 125125m back.

Akshi vs Toshi Triangle Debate (Page 134)

  • Akshi: Perimeter is 9 units.
  • Toshi: It’s more than 9 units.
  • Reasoning: The diagonal of a square is longer than its side. The “slanted” lines in the triangle on the grid are diagonals of the grid squares. Their length is greater than 1 unit. Therefore, the sum is greater than just counting grid lines. Toshi is correct.