A car started from town A at 7am and reached town B at 9am. Along the same road, a bicycle rider started from town B at 5am and reached town A at 12pm. At what time did they cross each other?

How can I solve this problem?

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- March 25th 2010, 07:59 PMgetonReasoning Problem
A car started from town A at 7am and reached town B at 9am. Along the same road, a bicycle rider started from town B at 5am and reached town A at 12pm. At what time did they cross each other?

How can I solve this problem? - March 25th 2010, 08:16 PMsa-ri-ga-ma
Let d km be the distance between the cities.

The velocity of the car Vc = d/2 km/h

The velocity of the bicycle Vb = d/7 km/h.

Find the position of the bicycle when the starts and the distance between the car and the bicycle. Let it be d1. Now start counting the time. If they meet at a point x km from the starting point of the car, they take the same time to reach that point. So

x/Vc = (d1-x)/Vb.

Find x in terms of d, then find t. - March 25th 2010, 11:21 PMrh1417help
In a certain class consisting of 36 students, some boys and some girls, exactly of one-third the boys and exactly one-fourth of the girls walk to school. What is the greatest possible number of students in this class who walk to school? and how?

- March 26th 2010, 12:51 AMsa-ri-ga-ma
In the class, let x boys and (36 - x) girls.

Number of students walking = x/3 + (36-x)/4 ...(1)

Simplify the equation.

Select the values of x, which is less than 36, such that number students who walk to the college must be the whole number. - March 27th 2010, 02:32 AMrh1417
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- March 27th 2010, 02:54 AMHallsofIvy
The weight of an organ tells you

**nothing**about its oxygen consumption.

By the way, it is not a good idea to keep appending new questions to the same thread- especially if you were not the one who started the thread.