help w/ algebra 2 type stuff?

Question

two planes left an airport at noon. one flew east at a certain speed and the other flew west at twice the speed. the planes were 2700 miles apart in 3 hours. how fast was each plane flying?

lol i no ive learned this b4 but i just cant rmbr wat to do, can u help?

Answer 1

let x be the speed of one airplane going East. Then 2x is the speed of the airplane going West.

The two airplanes are 2700 miles apart after 3 hrs. That means how much of the distance each airplane cover in 3 hrs will together add to 2700 miles

distance = speed * time

airlane going West:
d = 3x

airplane going East
d = 3(2x)
d = 6x

3x + 6x = 2700
9x = 2700
x = 300

airplane going East: 300 mi/hr
airplane going West: 600 mile/hr

Answer 2

So let's call one airplane's speed x, and the other one 2x.

When the speeds are added together, they result in (2700 miles/ 3 hours), which is 900 miles per hour.

So, x + 2x = 900 mph.

3x = 900 mph.

x = 300 mph.

Then one airplane's speed is 300 mph, and the other's must be 600 mph.

Solved!

**** Edit: Your first answerer makes the mistake of subtracting the speeds, which you would do if they were going in the same direction. But since your problem states they are going opposite directions, you need to *add* the speeds. To imagine this, picture that one plane has gone 1 mile east, and the other has gone 2 miles west. Then they are 3 miles apart from each other, which you get by adding, not subtracting.

*** Edit 2: Oh, well, I guess now Answerer 1 has changed her mind.

*** schs_gurl: From the Yahoo! Answers community guidelines: "Posting filler answers to a question in an effort to be first to answer, or copying and pasting other members’ answers, are also forms of cheating."

That's what bothers people. We're supposed to be helping Sizzlefritz, not gaming for points.

Answer 3

I think 3x + 6x = 2700

plane 1 flies at 300 mph east and after 3 hours traveled 900 miles

plane 2 flew 600 mph west and after 3 hours covered 1800 miles

remember the word DIRT

distance = rate x time

distance = 2700 miles
time = 3 hours
rate one is 2 times as fast as the other

Answer 4

Let the slower plane travel at x m.p.h., so the faster plane flew at 2x m.p.h.

Using distance travelled = average speed x time taken, and since they are flying in opposite directions, their combined speed will be 3x m.p.h., then

2700 = 3*3x, so

2700 = 9x, so

2700/9 = x, so

x = 300 m.p.h.

So, the two planes were flying at 300 m.p.h., and 600 m.p.h.

Hope this helps, Twiggy.

Answer 5

Plane one was going 300MPH while plane two was going 600MPH.

First you must know that 2700/3 is the sum of the two speeds, which is 900 miles per hour.

so then you know that x+2x=900MPH is your equation.
x + 2x = 900 mph.
then you add the X's
3x = 900 mph.
then divide the 900 by three and get
x = 300 mph for one plane.
then to find plane two you multiply that by 2
300*2
and get 600mph for plan one.

*check your answer*

then is you look at it after 3 hours plane one would have been 900miles away from the starting point and plane two would have been 1800 miles away from the starting point and you know that to find the distance between then you would have to add the distances because they were going in different directions and you would get 2700miles. Does this sound like the beginning problem?





**Timothy H** Yes i caught that, and thats y i re-did it and desided to show my work. thanks for pointing that out though.

Answer 6

you recognize, by using skill of the information, that the line is going by using way of components (2,2) and (0,10). The slope of the line is (2-10)/(2-0)=-8/2=-4. indoors the form of slope and y-intercept, the equation you're finding for is y=-4x+10.

Answer 7

...........Rate ......Time.....Distance
East......x............. 3 3x
West.....2x...........3............6x
(Distance = Rate X Time)
3x + 6x =2700
9x=2700
x=300
Eastbound flying @ 300miles per hour
Westbound flying @ 600 miles per hour