#1. Elena bicycles 4 km/h faster than Carlos. In the same time it takes Carlos to bicycle 51 km, Elena can bicycle 63 km. How fast does each bicyclist travel?
Carlos travels ??? km/h
Elena travels ??? km/h
#2. To determine the number of deer in a game preserve a conservationist catches 329 deer, tags them and lets them loose. Later, 624 deer are caught; 208 of them are tagged. How many deer are in the perserve?
THANK YOU SOOOO MUCH!!!!
2007-12-25 14:05:39 · 7 answers · asked by Tank 2 in Science & Mathematics ➔ Mathematics
Let x = Carlos' rate of bicycling
x + 4 km/hr = Elena"s rate of bicycling
at time t, Carlos bicycled 51 km while Elena bicycled 63 km.
t of Carlos = t of Elena
distance Carlos/rate of Carlo = distance Elena/rate of Elena
51 km/x = 63km/(x + 4)
51(x + 4) = 63x
51x + 204 = 63x
51x - 63x = - 204
-12x = - 204
x = - 204/-12
x = 17 km/hr, rate of bicycling of Carlos ANS
17 + 4 = 21 km/hr, rate of bicycling of Elena ANS
Hope I help you.
teddy boy
2007-12-25 15:34:14 · answer #1 · answered by teddy boy 6 · 0⤊ 0⤋
#1: the standard equation for relating distance speed and time is dist = speed x time
you are told: speed Elena = speed Carlos +4 km/hr; write this as se=sc+4
Elena: 63=se x t, or we can write this as:
63=(sc+4)xt or
63= sc x t + 4 x t
Carlos: 51=sc x t,
now, since we know that sc x t=51, we subsitute that into the equation:
63=sc x t + 4 x t or 63= 51+4 x t which tells us that t=3hrs
we can use this to show that Elena travels at 63=3 x se or
se = 21 km/hr, and Carlos travels at 17 km/hr
2007-12-25 22:19:33 · answer #2 · answered by kuiperbelt2003 7 · 0⤊ 0⤋
Solve via simultaneous equations.
Let E represent Elena's speed, let C represent Carlos'.
Then E = C+4
51C = 63E
Substitute 1 in 2:
51C = 63(C+4)
Solve for C:
51C = 63C + 252
12C = -252
C = -21 km/h
Substitute in 1:
E = C+4
E = -21 + 4
E = -17
2007-12-25 22:26:49 · answer #3 · answered by Robert S 7 · 0⤊ 0⤋
#2 I would like to think that you would subtract 208 from 624 and add the solution to 329... and the answer you get is 745...but i could be wrong...
2007-12-25 22:16:06 · answer #4 · answered by Anonymous · 0⤊ 0⤋
# 2 If we assumed that all untagged deer are caught, the total number of deer in the preserve is 745.
2007-12-26 07:12:07 · answer #5 · answered by detektibgapo 5 · 0⤊ 0⤋
#1
Elena 63km in x hrs..
Carlos 51km in x hrs..
difference in speed is 4kph
63km/xhrs - 51km/xhrs = 4km/hr
u'll get 12km/x hrs = 4km/hr
x = 3.. meaning they traveled for 3 hrs..
Carlos
51/3 = 17kph
Elena
63/3 = 21kph
2007-12-25 23:48:14 · answer #6 · answered by engle 2 · 0⤊ 0⤋
i think #2 is 745
but idk how to do #1.
let me know what they are please. email me.
2007-12-25 22:25:40 · answer #7 · answered by Anonymous · 0⤊ 0⤋