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#1 2006-11-09 09:27:56

Joel
Member
Registered: 2006-11-09
Posts: 5

speed and distance

The train traveled at s meters per minute for d meters and arrived t minutes late to its destination. How fast should the train have traveled to make it to its destination on time?

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#2 2006-11-09 09:32:57

Joel
Member
Registered: 2006-11-09
Posts: 5

Re: speed and distance

The train traveled at s meters per minute for d meters and arrived t minutes late to its destination. How fast should the train have traveled to make it to its destination on time?

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#3 2006-11-09 10:17:03

~~freespirit~~
Member
Registered: 2006-11-09
Posts: 2

Re: speed and distance

well, i must admit i can't figure that 1 out...

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#4 2006-11-09 10:39:37

luca-deltodesco
Member
Registered: 2006-05-05
Posts: 1,470

Re: speed and distance

the train will cover Ts metres, in T minutes
it arrived t minutes late.

i.e. d = s(T+t), you want the train to be on time, so t must be 0,

i.e. s(T+t) = ST, where S is the new speed.
so the speed it should have travelled at will be

where T is the time it should take to reach the destination, and t is how many minutes it was late, when travelling at s metres per
minute

if you dont want to have T in the equation, then take d = s(T+t) = sT + st, then sT = d - st, and

i.e.

Last edited by luca-deltodesco (2006-11-09 10:42:21)


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