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A bus travels for x hours at a speed of (x+2) km/h. If the distance travelled is 15km,...

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christiano-cr7 | Salutatorian

Posted July 17, 2013 at 10:28 AM via web

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A bus travels for x hours at a speed of (x+2) km/h. If the distance travelled is 15km, find the speed of the bus.

 

 

 

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jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted July 17, 2013 at 10:35 AM (Answer #1)

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Distance travelled `= (speed)xx(time)`

speed = (x+2)

Time = x

Distance travelled = 15

 

`x(x+2) = 15`

`x^2+2x = 15`

`x^2+2x-15 = 0`

`x^2+5x-3x-15 = 0`

`x(x+5)-3(x+5) = 0`

`(x-3)(x+5) = 0`

`x = 3` or `x = -5`

 

Since x represent time it cannot be a negative value. So x = 3.

Speed of the bus `= 3+2 = 5`

 

So the speed of the bus is 5km/h.

 

you better walk rather than going this kind of a bus. :)

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