Posted by **Lauren** on Tuesday, March 16, 2010 at 12:06am.

Erin takes a total of 5 hours in her boat to travel a distance upriver and return downriver the same distance. If the time traveling upriver is twice the time traveling downriver, how many hours does each trip take?

How do I put this into two equation and use the matrix to solve it?

- math -
**FredR**, Tuesday, March 16, 2010 at 3:45am
u = 2d

or

u - 2d = 0

u + d = 5

so the matrix would be

1 -2 0

1 1 5

add -1 times the 1st row to the 2nd row. Then you get

1 -2 0

0 3 5

multiply the 2nd row by 1/3:

1 -2 0

0 1 5/3

The 2nd row tells us that d = 5/3, so u = 10/3

- math -
**PsyDAG**, Tuesday, March 16, 2010 at 11:02am
I don't know about the matrix, but it is not necessary to solve the problem.

x = time traveling down river

2x = time traveling up river.

x + 2x = 5

3x = 5

x = 5/3 hour = 1 hour, 40 minutes

2x = ?

I hope this helps.

## Answer this Question

## Related Questions

- Math word problem - The Mad River flows at a rate of 3 km/h. In order for a boat...
- math - distance = rate x time or d = r*t car traveling 40 mi/hr goes 40 mi/hr x ...
- Physics - A fisherman notices that his boat is moving up and down periodically, ...
- Physics - A fisherman notices that his boat is moving up and down periodically, ...
- Physics Easy one - A fisherman notices that his boat is moving up and down ...
- college physics - A fisherman notices that his boat is moving up and down ...
- Math! Algebra 1! - A boat is traveling in a river with a current that has a ...
- Algebra - The current of a river moves at 3 miles per hour. It takes a boat 3 ...
- College Physics - A fisherman notices that his boat is moving uo and down ...
- Math-Algebra - A car takes 3 hours to travel a distance of 240 km with a speed ...