Layla traveled a total distance of 450 miles initially by car with an average speed of 60 miles/hour, and subsequently by train with an average speed of 110 miles/hour. Total time required is 5 hours. Find the time spent on the train.
A
3 hours
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B
6 hours
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C
9 hours
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Solution
The correct option is A3 hours Let the time traveled by car is x hours, and by train is y hours. ∴ Distance covered by car =x×60 miles
And, distance covered by train =y×110 miles
Total distance covered =450 miles ∴60x+110y=450 ⇒6x+11y=45...(a)
Total time required =5 hours ∴x+y=5
Multiply by 6 in both sides. ⇒6x+6y=30...(b)
Subtract (b) from (a) to eliminate 6x. 6x+11y−(6x+6y)=45−30 ⇒11y−6y=15 ⇒5y=15 ⇒y=3