Accepted answer
Answer included
The question how long is 80 minutes is answered by expressing 80 minutes in familiar time units: hours-and-minutes form and decimal hours.
Key fact: \(1\ \text{hour} = 60\ \text{minutes}\) (exact).
Therefore, converting minutes to hours is division by \(60\), and converting to “hours and minutes” uses quotient and remainder.
Convert 80 minutes to hours and minutes
Divide 80 by 60 to find the number of full hours and the leftover minutes:
\[ 80 = 60 \times 1 + 20 \]The quotient is \(1\) hour and the remainder is \(20\) minutes, so:
\[ 80\ \text{minutes} = 1\ \text{hour}\ 20\ \text{minutes} \]Convert 80 minutes to decimal hours
Decimal hours treat the hour as the base unit:
\[ t_{\text{h}} = \frac{80}{60} = \frac{4}{3} = 1.333333\ldots\ \text{hours} \]Rounded to two decimal places: \(1.33\ \text{h}\). Rounded to four decimal places: \(1.3333\ \text{h}\).
Quick reference table
| Minutes | Hours (decimal) | Hours and minutes |
|---|---|---|
| 60 | \(\dfrac{60}{60} = 1\) | 1 h 0 min |
| 75 | \(\dfrac{75}{60} = 1.25\) | 1 h 15 min |
| 80 | \(\dfrac{80}{60} = 1.3333\ldots\) | 1 h 20 min |
| 90 | \(\dfrac{90}{60} = 1.5\) | 1 h 30 min |
| 120 | \(\dfrac{120}{60} = 2\) | 2 h 0 min |
Visualization: 80 minutes on a 0–120 minute timeline
Common checks
- Reverse check: \(1\ \text{h}\ 20\ \text{min} = 60\ \text{min} + 20\ \text{min} = 80\ \text{min}\).
- Decimal check: \(1.3333\ldots\ \text{h} \times 60\ \dfrac{\text{min}}{\text{h}} = 80\ \text{min}\).
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