飛航百科

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標題:

Ratio and Rate (2)

發問:

1. A wheel rotates 15 turns to travel a distance of 27m. Find the number of rotations for travelling 405m. 2. Anne typed 1000 words at a speed of 30 words/min, and then typed 750 words at a speed of 40 words/min. Find her average typing speed. * Please show all the steps.

最佳解答:

1. A wheel rotates 15 turns to travel a distance of 27m. Find the number of rotations for travelling 405m Let the number of rotations for travelling 405m be (a) 27/15 = 405/a 27a = 405 x 15 27a = 6075 a = 225 // The number of rotations for travelling 405m is 225. 2. Anne typed 1000 words at a speed of 30 words/min, and then typed 750 words at a speed of 40 words/min. Find her average typing speed. 1000 ÷ 30 = ( 100/3 ) = (400/12) minutes 750 ÷ 40 = ( 75/4 ) = ( 225/12 )minutes She uses (400/12) + ( 225/12 ) minutes to type ( 1000 + 750 ) words 1750 ÷ ( 625/12 ) = 168/5 = 33.6 words/min Her average typing speed is 33.6 words/min 2007-03-01 18:50:35 補充： 33.6 ≈ 34 (correct to the nearest 1 word )Her average typing speed is about 34 words/min

其他解答:A9A39959EDCC7BE3