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`
1 Answer | Add Yours
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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