ShmoopTube

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Here’s a shmoopy question for ya…

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Batman totally forgot he was supposed to be back in Gotham for a… business meeting in about an hour.

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The Batmobile, traveling at an average of 60 mph, took a certain amount of time to cover

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a distance of 80 miles.

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How much more ground can it cover traveling at a speed of 75 mph in the same amount of time?

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Here are the potential answers…

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So… what is this question asking?

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It’s a distance, rate and time problem which we have to just think through.

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First, let’s put everything in the same units.

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In this problem, we’re all miles… Batman wouldn’t dare fool around with kilometers.

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That’s Alfred’s thing.

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The Batmobile was going 60 miles an hour, so it can travel, well… 60 miles

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in one hour… or 1 mile per minute.

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So if it goes 80 miles, then it’s travelled 80 minutes.

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But the key thing to glean here is that the Batmobile went for 80 minutes… or an hour

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and 20 minutes… or 1.33 hours.

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So now what if the Batmobile didn’t hit much traffic and was instead going 75 miles an hour?

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To figure out how far it would have driven in that same amount of time, we multiply its

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rate of 75 mph by 1.33 and we get… about 100 miles.

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So the DIFFERENCE between the two distances is 20 miles.

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Answer A. As in, "Alfred."

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