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Need some major help with algebra?
I have two problems that keep tripping me up with my math homework. Can someone please help me?
The first problem is:
Station A is 128 miles east of Station B. A train leaves station A headed due west at 60 miles per hour. At the same time, another train leaves station B and travels due east a 68 miles per hour. How long until they pass each other?
The second is:
I mixed nuts that are worth $2/lb with a bag of trail mix worth $0.80/lb. The resulting mix is worth $1.20/lb. If I have 10 pounds of the final mix, how much of each ingredient did I add?
Please please help me. :-/
3 Answers
- 1 decade agoFavorite Answer
TRAIN PROBLEM
So, we are trying to find an equation to describe the two trains locations. Imagine the track is a number line starting at 0, and ending at 128.
Train B starts at 0, and increases its location at 68 miles an hour. So, if we let 't' equal the amount of time..
Location = 0 + 68*t
Train A starts at mile 128, and decreases that mile marker at 60 miles an hour.
Location = 128 -60*t
Since were trying to find out when they cross, when their locations are the same, we say
68*t = 128 - 60*t
which solved is.. t = 16
_______________________________________________________________
NUTS PROBLEM
We have two different equations we are given, An equation for the value of the nuts, and an equation for the total weight.
Price:
We will say that the number of lbs mixed nuts is x, and the number of lbs of trail mix is y. The resulting equation is...
2*x + .8*y = 1.2*(x+y) <--we need this (x+y) because the 1.2 is given in price per lb.
Weight:
This is pretty straight forward
x+y = 10
now we need to solve this system of equations
2*x + .8*y = 1.2*(x+y)
2*x + .8*y = 1.2*10 <-- From the second equation
2*x + .8*y = 12
2*x = 12 - .8y
x = 6 - .4y
Now, substitute this into the second equation
x+y=10
6 - .4y + y = 10
6 +.6y = 10
.6y = 4
y = 6.6667
now, re-use our new y value in the second equation to find x
x+y=10
x+6.6667=10
x = 3.33333
There we go, 3.33333 lb mixed nuts, 6.66667 lb trail mix
- SumDudeLv 71 decade ago
60 mph in one hour + 68 mph in the same hour but from the opposite direction = 128 mi traveled; so they meet/pass at the 1 hour mark.
Matthew was fine on the train until he messed up his math on the last equation. Always double ck your answers, and everybody else's !!
Source(s): simple logic - ?Lv 45 years ago
Parallel. Make the slope the identical and alternative within the two for x and the three for y then resolve. a. y=3x-three Perpendicular. The slope is the reverse reciprocal and plug within the (two,three) once more. b. y=-a million/three X + eleven/three I edited, considering the fact that did perpendicular with reverse and no longer reverse reciprocal.