Example

Converting 9 Weeks to Minutes Using Chained Conversion Factors

When the starting and target units are not directly related by a single conversion factor, multiple conversion factors can be chained together in one expression. Each factor equals 11, so multiplying by several of them still preserves the original value — only the unit changes at each step.

To convert 99 weeks to minutes, chain three conversion factors: weeks to days, days to hours, and hours to minutes.

  1. Start with the given measurement: 9 weeks9 \text{ weeks}.
  2. Write 11 as three successive conversion factors: 9 wk17 days1 wk24 hr1 day60 min1 hr\frac{9 \text{ wk}}{1} \cdot \frac{7 \text{ days}}{1 \text{ wk}} \cdot \frac{24 \text{ hr}}{1 \text{ day}} \cdot \frac{60 \text{ min}}{1 \text{ hr}}
  3. Cancel the common units: "wk" cancels with "wk," "days" cancels with "day," and "hr" cancels with "hr," leaving only minutes.
  4. Multiply the numerators and denominators: 972460 min1111=90,720 min\frac{9 \cdot 7 \cdot 24 \cdot 60 \text{ min}}{1 \cdot 1 \cdot 1 \cdot 1} = 90{,}720 \text{ min}

Therefore 99 weeks =90,720= 90{,}720 minutes. This example extends the single-conversion-factor technique by stringing together several factors in one expression, with each intermediate unit appearing once in a numerator and once in a denominator so that it divides out.

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Updated 2026-04-21

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