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Bunuel
A bicycle tire has a diameter of 70 centimeters. Approximately how many revolutions does the tire make if the bicycle travels 1 kilometer. (1 kilometer = 100 meters = 100000 centimeters)

A. 150
B. 450
C. 900
D. 1500
E. 2200
(circumference)*(# of revolutions) = Distance, so

Number of revolutions =\(\frac{Distance}{circumference}\)

Circumference: \(\pi d=70\pi=(70*\frac{22}{7})\approx{220}cm\)

Distance = \(100,000 cm\)

Number of revolutions:
\(\frac{Distance}{circumference}=\frac{100,000cm}{220cm}\approx{455}\) revolutions

Answer B
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Bunuel
A bicycle tire has a diameter of 70 centimeters. Approximately how many revolutions does the tire make if the bicycle travels 1 kilometer. (1 kilometer = 100 meters = 100000 centimeters)

A. 150
B. 450
C. 900
D. 1500
E. 2200


\(Number of revolutions =\frac{Distance}{circumference}\)

Circumference = \(\pi d=70\pi=(70*\frac{22}{7})\approx{220}cm\)

Distance = \(100,000 cm\)

Number of revolutions = \(\frac{Distance}{circumference}=\frac{100,000cm}{220cm}\)

Here we can make 220 to be 200 to ease the calculation. The answer choices helps to make the approximation.

Number of revolutions = \(\frac{Distance}{circumference}=\frac{100,000cm}{200cm}\) = \(500\)

The number must be less than 500.

450 is the closest to 500

Answer B
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Bunuel
A bicycle tire has a diameter of 70 centimeters. Approximately how many revolutions does the tire make if the bicycle travels 1 kilometer. (1 kilometer = 100 meters = 100000 centimeters)

A. 150
B. 450
C. 900
D. 1500
E. 2200

(note: although we are using the given conversion, 1 kilometer = 1,000 meters)

The circumference of the tire is 70π = 70 x 3.14 = 219.8 cm, which is about 220 cm. Thus, 1 revolution of the tire is about 220cm.

Since 1 km = 1,000 m and 1 m = 100 cm, so 1 km = 1,000 x 100 = 100,000 cm. Thus in 100,000 cm, the number of revolutions is 100,000/220 ≈ 454 ≈ 450 revolutions.

Answer: B
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Bunuel
A bicycle tire has a diameter of 70 centimeters. Approximately how many revolutions does the tire make if the bicycle travels 1 kilometer. (1 kilometer = 1,000 meters = 100,000 centimeters)

A. 150
B. 450
C. 900
D. 1500
E. 2200

Diameter = 70cm
Circumference = 210cm
1km = 1000m = 100000cm
100000/210 = 1000/2 = 500

Answer choice B.
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Rule of three is very practical to the gmat test.
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