Question

Score: 0 of 1 pt

Answer 1

Answer:

Step-by-step explanation:

Let +s+ = the speed of the passenger train

+s+-+20%5D+ = the speed of the freight train

Let +t+ = time in hours for both trains

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Equation forpassenger train:

(1) +280+=+s%2At+

Equation for freight train:

(2) +180+=+%28+s-20+%29%2At+

------------------------

(1) +t+=+280%2Fs+

Substitute (1) into (2)

(2) +180+=+%28+s-20+%29%2A%28+280%2Fs+%29+

(2) +180s+=+280s+-+5600+

 

(2) +100s+=+5600+

(2) +s+=+56+

and

+s+-+20+=+36+

The speed of the passenger train is 56 mi/hr

The speed of the freight train is 36 mi/hr

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check:

(1) +280+=+56%2At+

(1) +t+=+5+

and

(2) +180+=+%28+56-20+%29%2At+

(2) +180+=+36t+

(2) +t+=+5+

OK