Help me with this math word problem:

[Snickerdoodle]

A bridge 56 meters long was constructed across a river. Finish the problem in such a way that the width of the river can be found.

 

:tongue_smilie:

 

Either I am missing something, or I am losing my mind.

[*********]

Wouldn't you need to know how far it was, on each side, from the end of the bridge to the edge of the river in order to find the width of the river?

[gardening momma]

Hmm...well the Mackinac Bridge between Michigan's Upper and Lower Peninsulas is supposed to be 5 miles long, but a lot of that is over land! :tongue_smilie: Can't help, sorry.

[Perry]

A bridge 56 meters long was constructed across a river. Finish the problem in such a way that the width of the river can be found.

 

:tongue_smilie:

 

Either I am missing something, or I am losing my mind.

:confused: Did this come from a homeschool math curriculum?

[gardening momma]

What math program and what level is this? Maybe you're supposed to write it algebraicly (sp?) so that if you knew how much bridge is over land you can solve the problem?

 

if y=length of bridge over land

x=width of river

56-y=x

[Sputterduck]

I have an answer... the river is less than 56 meters wide.

 

Other than that, I think you need for info and they screwed up.

[Tap]

A bridge 56 meters long was constructed across a river. Finish the problem in such a way that the width of the river can be found.

 

:tongue_smilie:

 

Either I am missing something, or I am losing my mind.

 

Is it supposed to be a creative word problem, that you provide some of the answer to?

 

An answer may be:

 

'A 56 meter bridge spanning a river that has 10 meters distance between each bank and its corresponding bridge entrance, would have a river width of 36 meters.'

 

Or

 

'there is not enough data to answer the question'.

[Snickerdoodle]

Russian grade two math translated by Chicago University. I have caught a couple of typos or misprints. I wonder if this is one of them.

 

Here is the first problem on that page for comparison:

 

There were 18 black currant bushes in a garden, 6 fewer white currant bushes than black currant bushes, and 5 more red currant bushes than white currant bushes. How many red currant bushes were there in the garden?

 

(18 - 6) + 5 =

[forty-two]

A bridge 56 meters long was constructed across a river. Finish the problem in such a way that the width of the river can be found.

I like this problem - it is forcing you to make all your assumptions explicit; the more I think about it, the more I come up with.

 

For one, you need to know how much of the bridge was over water and how much was over land. Also, you need to know the orientation of the bridge with respect to the river - is it perpendicular to the river, or at a different angle? Also, you're assuming that the bridge is a straight line. You're also assuming that they want the width of the river right where the bridge crosses - depending on where the bridge was placed, that could be substantially narrower than the rest of the river in that area.

 

So you could complete the problem by saying that the bridge starts and ends right at the edges of the river, and it is perpendicular to the the river, which would give you the width of the river at that point as equal to the length of the bridge.

 

Or you could say that the bridge starts and ends 8m inland from the banks of the river respectively, and crosses the river at a 45 degree angle. That would require quite a bit more math (more than I want to do in my head at the moment ;)).

 

Clear as mud? :tongue_smilie:

[Snickerdoodle]

I like this problem - it is forcing you to make all your assumptions explicit

 

Now that I think about some of the previous problems, I think you are right.

[Dawn in OH]

I have an answer... the river is less than 56 meters wide.

 

 

 

That was going to be my smarty pants answer.