Homework Help

John goes to school and returns home at speed x km/h and (x + 1) km/h respectively. The...

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christiano-cr7 | Salutatorian

Posted September 28, 2013 at 6:33 PM via web

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John goes to school and returns home at speed x km/h and (x + 1) km/h respectively. The school is 2 km from John’s home and the total time for the two journeys is 54 minutes. Which of the following equations can be used to find x?

A) `x/2+(x+1)/2= 54/60`

B) `2/x+2/(x+1) =54/60`

C) `[x+(x+1)] * (1/2) / 4 =54/60`

D) `4/([x+(x+1)] * (1/2)) = 54/60`

E) `2x+2(x+1)=54/60`

1 Answer | Add Yours

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

Posted September 28, 2013 at 6:40 PM (Answer #1)

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Let us say to go to school John takes `t_1` hours and for the return it takes `t_2` hours.

`xt_1 = 2`

`t_1 = 2/x`

`(x+1)t_2 = 2`

`t_2 = 2/(x+1)`

The total time for two trips is 54 minutes which is `54/60` hrs.

`t_1+t_2 = 54/60`

`2/x+2/(x+1) = 54/60`

So the correct equation would the equation at answer B)

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