Depth · one concept from first principles · step 2 of 4
The distance from Jeju to Ulsan is . A typhoon travelling from Jeju toward Ulsan covers distance (in ) at a rate of per hour. How many hours and minutes does it take to go from Jeju to Ulsan?
The rate of distance to time being 144 means the storm covers 144 kilometers in each hour.
144 km every hour.
6.RP.A.2Analyze The UnitsIf the rate is distance over time, then time is distance over the rate.
The journey takes 2.25 hours.
6.RP.A.3Work BackwardsThe time taken is the distance divided by the rate.
A rate of means the storm covers kilometres in each hour, so the whole distance is that many equal hourly stretches.
Asking how many of those stretches fit into is the division that undoes the multiplying.
The 0.25 of an hour is a quarter of 60 minutes.
That is 2 hours 15 minutes.
6.RP.A.3Identify SubproblemsA rate is a division sentence -- turn it around and it gives back whichever quantity is missing.
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