word problems

[lcase]

A cement walk of uniform width is to be laid around a rectangular flower bed that is 60 ft long by 30 ft wide. If the area of the walk is to be 425 sq ft., what is the width of the walk?

11.(60+2X)(30+2X)-1800=425
When I solve and use the formula it comes out with a square root of 2.

Pipe A can fill a swimming pool alone in 12 hours. Pipe B in 9 hours. If both pipes input water into the pool for two hours, and hen pipe B is used alone to finish filling the pool, how long would it take to fill the pool?

17. (1/12 + 1/9)2+ 1/9X=1
I am getting 11/2 hours, not 15/2

Pipe A can fill a pool alone in 4 hours. Pipe B in 6 hours, and pipe C alone in 10 hours. If pipes A and B are used for 1 hour and then B and C are used to finsih filling the pool how long will it take to fill the pool?

19.1/4+ 1/8 + 1/10???? Can't get it any farther on this one...

Pipe A can fill a pool alone in 4 hours, Pipe B can fill the same pool in 8 hours, and pipe C can empty it all in 8 hours. Pipes A and B are used to input water into the pool for 1 hour, at which time pipe A is closed and pipe C is opened. After pipe C is opened how much additional time will it take to finish filling the pool.

20. same problem???

Traveling at full speed on a river, ti takes 4 hours for a motor boat to travel 18 miles upstream and 21 miles back downstream. If the curren't speed is 2 mph, what is the mx speed of the boat is still water.

27. 21/X-2 + 18/X+2 = 4, when plugged in I am getting another square root and not a number///

Traveling at full speed on a river it takes 5/2 hours for a man in a motorboat to travel 18 miles downstream and 8 miles back upstream. If the max speed of the boat in still water is 10 mph what is the speed of the current

29. 18/X-10 = 8/X = 5/2 I don't come up with the right solution on this one....

 

[tkhunny]

A cement walk of uniform width is to be laid around a rectangular flower bed that is 60 ft long by 30 ft wide. If the area of the walk is to be 425 sq ft., what is the width of the walk?

11.(60+2X)(30+2X)-1800=425
When I solve and use the formula it comes out with a square root of 2.

Is that a problem? If you managed ½(35*sqrt(2) - 45), then you did it just fine. Check your answers.

Pipe A can fill a swimming pool alone in 12 hours. Pipe B in 9 hours. If both pipes input water into the pool for two hours, and hen pipe B is used alone to finish filling the pool, how long would it take to fill the pool?

17. (1/12 + 1/9)2+ 1/9X=1
I am getting 11/2 hours, not 15/2

You solved of X just fine. Now answer the question. X+2!

Pipe A can fill a pool alone in 4 hours. Pipe B in 6 hours, and pipe C alone in 10 hours. If pipes A and B are used for 1 hour and then B and C are used to finsih filling the pool how long will it take to fill the pool?

19.1/4+ 1/8 + 1/10???? Can't get it any farther on this one...

I don't understand why this one is different from the last one.

x = time to fill the pool AFTER the first hour.
(1/4 + 1/8)*1 + (1/8 + 1/10)*x = 1 Answer is x+1

Pipe A can fill a pool alone in 4 hours, Pipe B can fill the same pool in 8 hours, and pipe C can empty it all in 8 hours. Pipes A and B are used to input water into the pool for 1 hour, at which time pipe A is closed and pipe C is opened. After pipe C is opened how much additional time will it take to finish filling the pool.

20. same problem???

This is just a thought question. After 1 hour, we have 1/4 + 1/8 = 3/8. At that time, B & C work perfectly against each other. It will NEVER fill up.

I'm tired. I answered as many as I did ONLY because you started with showing your work.