The speed of train A is 12 mph slower than the speed of train B. Train A travels 230 miles in the same time it takes train B to travel 290 miles. Find the speed of each train.
The speed of train A is ___ mph.
The speed of train B is ___mph.
2007-05-11 15:19:42 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
OMG I had that same problem a few weeks ago, but I have no idea how to solve it! I am sooo sorry
2007-05-11 15:23:18 · answer #1 · answered by Sara B 3 · 0⤊ 3⤋
Distance = Rate x Time
Write an equation for Train A:
230 = (R - 12) T
Write another equation for Train B:
290 = RT
Solve one equation for R or T
290/T = R
Substitute into the other equation
230 = (290/T - 12) T
Distribute
230 = 290 - 12T
Subtract 290
-60 = -12T
Divide by -12
5 = T
Substitute 5 for T in either equation and solve.
230 = (R - 12) 5
46 = R - 12
58 = R
The speed of train B is 58 mph
The speed of train A is 12 MPH slower = 46 mph
2007-05-11 15:32:29 · answer #2 · answered by suesysgoddess 6 · 2⤊ 0⤋
You need to use the D = RxT formula, and equate the times. By reworking the formula, you get T = D/R. Let B's speed be b, and a's speed would be b-12. So for train A, T = 230/(b-12). For train B, T = 290/b. Since the times are equal, you get 230/(b-12) = 290/b. Cross multiply, and you have 230b = 290(b-12). Simplify, you get 230b = 290b - 3480, so by subtracting 230b from both sides, you're left with 0 = 60b - 3480. Add 3480 and divide by 60 to get b = 58. So train b's speed is 58 mph, and train A's speed is 58 - 12 = 46 mph. To check, divide 230 by 46 (= 5) and 290 by 58 (= 5).
2007-05-11 15:35:52 · answer #3 · answered by TitoBob 7 · 0⤊ 0⤋
Let speed of train B = x mph
Let speed of train A = (x - 12) mph
t = 230 / (x - 12) and t = 290 / x
230 / (x - 12) = 290 / x
230 x = 290 (x - 12)
23 x = 29 x - 348
6x = 348
x = 58
Train B : 58 mph
Train A : 46 mph
2007-05-11 23:14:40 · answer #4 · answered by Como 7 · 0⤊ 0⤋
The speed of train A is 46 mph
The speed of train B is 58 mph
2007-05-11 15:33:14 · answer #5 · answered by shark7777 3 · 1⤊ 0⤋
let speed of train A be Va and the speed of train B be Vb
Va=Vb-12
since velocity is distance/time
let T be the time that each train travels since Ta=Tb=T
Va=230/T and Vb=290/T
rearranging each in terms of T,
T=230/Va and T =290/Vb
therefore
230/Va=290/Vb
replacing Va
230=(Vb-12)*290/Vb
230=290-3480/Vb
3480/Vb=60
3480=60Vb
Vb=58mph
and
Va=46mph
2007-05-11 15:37:09 · answer #6 · answered by theanswerman 3 · 0⤊ 0⤋
speed = distance divided by time
a
distance = 230
time = 230 miles divided by 12 miles per hour
and same for b
2007-05-11 15:27:18 · answer #7 · answered by Anonymous · 0⤊ 2⤋
A + 12 = B
A x t = 230
B x t = 290
t = 230/A
B = 290 x A/230
B = 1.26 x A
A + 12 = 1.26 x A
A = 46.15 mph
B = 58.15 mph
2007-05-11 15:33:55 · answer #8 · answered by misoma5 7 · 0⤊ 2⤋
GUESS :D
2007-05-11 15:25:20 · answer #9 · answered by bulletprooflonliness 4 · 0⤊ 2⤋