1) The length of a rectangular playing field is 5ft less than twice it's width.If hte perimeter of the playing field is 230 ft,find the length and width of the field .
2) A byciclist rode into the country for 5h. In returning her speed was 5mi/h faster and the trip took 4h.tWhat was her speed each way?
2007-11-28 04:04:24 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
[05]
Let the width of the field be w ft
So its length is 2w-5 ft
According to the problem
2(w+2w-5)=230
2(3w-5)=230
3w-5=230/2=115
3w=115+5=120
w=120/3=40
Therefore the width of the field is 40ft and its length is 40*2-5 or 75 ft
2)Let her first speed be x mph and so her return speed is (x+5)mph
According to the problem
5x=4(x+5)
5x=4x+20
5x-4x=20
x=20
Therefore her initial speed was 20 mph and her return speed was 20+5 or 25 mph
2007-11-28 04:12:50 · answer #1 · answered by alpha 7 · 1⤊ 0⤋
x = width
2x-5 = length
6x-10 = perimeter = 230
6x = 240 --> x = 40 = width
2x- 5 = 75 = length
rt = d
5r = 4(r+5)
5r=4r +20
r= 20 = speed going
r+5 = 25 = speed returning
2007-11-28 12:13:01 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋
1) L=2W-5
2L+2W=230
Therefore 2(2W-5)+2W=230
6W=240
W=40
L=75
2) D=5R and D=4(R+5)
Therefore 5R=4R+20
R=20
going speed is 20 mph, returning is 25 mph
2007-11-28 12:09:10 · answer #3 · answered by RickSus R 5 · 0⤊ 0⤋
w = 40
l = 75...
2007-11-28 15:21:41 · answer #4 · answered by jst_askn 7 · 0⤊ 0⤋