Quantitative Reasoning question

[sakura]

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I like the solution given to the following problem as it seems more efficient than mine. However, I do not understand the solution given. Can someone please help me to understand?

Problem: An 8 lane highway costs $7,500,000/mile. If each lane measures 11ft. across, how much would it cost to pave a square mile of highway?

Solution given: Each lane is 11 ft across and there are 8 lanes, so its width is 88 ft. 5,280 ft/88 ft = 60, so 60 miles of this highway would represent one square mile. 60 x $7,500,000 = $450,000,000, so it would cost $450,000,000 to pave one square mile of highway.

I don't understand the division of the 5,280 ft/88 ft = 60 and why this equates to one square mile.

Please help and thanks for your time.

 

[Danny289]

1mile equal to 5280 feet
8x11=88 feet wide of highway

you can solve this way:

Area of 1 mile high way with 88 feet wide = 88 x 5250 f^2
Area of one square miles( base on feet) = 5280 x 5280 f^2


now question is how many of this highways will cover one square mile.


(5280 x 5280)/(88 x 5280) or your orginal equation: 5280/88
you know the rest......
hopefuly it helped

 

[sakura]

Thanks dan!! I was making this more difficult than its worth.🙂