Plz help me! plz plz plz!

[Straight edge man]

ok well i need help on a couple... :roll:
The first-
The perimeter of a rectange is 160 ft. One fourth the length is the same as twice the width. Find the dimensions of the rectangle.

The second-
On a fishing trip, Mariko caught twenty-four fish. She caught some rockfish averaging 2.5 lb. and some blufish averaging 8 lb. The total weight of the fish was 137 lb. How many of each kind of fish did she catch?

The third-
Safety Rent-A-Truck rents a truck at a daily rate of $41.95 plus 29 (cents) per mile. City Rentals rents the same size truck for $38.95 plus 31 (cents) per mile. For what mileage is the cost the same?

If you would help, many thanks.

 

[mathstresser]

your box dimensions should be 2x+2y=160. From what you said (1/4)x=2y.

You have two variables, and now you have two equations, so you can solve it.

I'm not quite sure about the fish. I came up with
R+B=F
2.5R+8B=137F
but that's only 2 equations for 3 variables, so something is missing...

hmmm... don't remember... maybe set up two equations and try to find where the intersect (graph....)

 

[Straight edge man]

hey thanks for the first one helped a lot but do you have any clue how to do the rental car one???? thanks a lot though =)

 

[mathstresser]

S=41.95x+.29y
C=38.95x+.31y

Sorry I can't be much help... you need to find where x and y meet... (x is number of days, y is number of miles)...

but I'm not exactly sure how.... It's been a long time since I've done those...

 

[Straight edge man]

ok thanks much =)

 

[Gene]

#2) Close
R+B=24
2.5*R+8*B=137
That gets rid of the third.

Use variable names that reflect what they stand for as R & B did.
You don't need a days variable 'cause it is per day driving M miles.

41.95+.29M = 38.95 + .31M

 

[Denis]

On a fishing trip, Mariko caught twenty-four fish. She caught some rockfish averaging 2.5 lb. and some blufish averaging 8 lb. The total weight of the fish was 137 lb. How many of each kind of fish did she catch?

r = rockfish, b = bluefish

r + b = 24 ; b = 24 - r

2.5r + 8b = 137
2.5r + 8(24 - r) = 137

Take over...


Safety Rent-A-Truck rents a truck at a daily rate of $41.95 plus 29 (cents) per mile. City Rentals rents the same size truck for $38.95 plus 31 (cents) per mile. For what mileage is the cost the same?

m = mileage

41.95 + .29m = 38.95 + .31m

Take over...