Approximately how many revolutions will be made by a car tire with a 15-inch diameter if the car travels 1⁄2 mile? Select
A) 669	B) 660	C) 360	D) 720	E) 1,440
Diameter of car tire = 15 inches   Radius of car tire = 7.5 inches = 7.5*2.54= 
<gadget id="calculator">7.5*2.54</gadget>
<output>19.05</output>
19.05 cm   Circumference of the car tire= 2*pi * 19.05 = 2 *3.14 *19.05= 119.63 cm   Distance traveled by car = .5 mile = .5 *1.6= 
<gadget id="calculator">.5 *1.6</gadget>
<output>0.8</output>
.8 km= 800 m = 8 * 10^4 cm   Number of revolutions =Distance traveled / Circumference of tire = 8 * 10^4 / 119.63 = 668.73   Since the answer choices are far apart we should use estimation in this question .   Ideally ,in the GMAT the conversion between units would be provided .   669nswer 669
<result>A</result>
Approximately how many revolutions will be made by a car tire with a 15-inch diameter if the car travels 1⁄2 mile?