How do you solve this math algebra problem?

Question

It says:
2y-a/3=a+3b/4

and one that says:

Two airplanes leave Dallas at the same time and fly in opposite directions. One airplane travels 80 mph faster than the other. After three hours, they are 2940 miles apart. What is the speed of each airplane?

PLEASE HELP ME!!!!!

I know the 1st one is unsolvable, i know that. But it needs to be reduced to the lowest/simplist form it can be. Sorry i didn't say that sooner. Thanks for the other answers!

Answer 1

For the first problem, I don't know what you're writing (on the left it could be (2y - a)/3, or 2y - (a/3), etc.), or which variable you're trying to solve for.

For the second, speed is distance divided by time, so speed times time is distance. If "s" is the speed of one plane, then we're told that the speed of the other is s+80. After 3 hours, the first one has traveled 3s miles and the second has traveled 3(s+80). Together the combined distances from the airport is 2940. So 3s + 3(s+80) = 2940. Solve this for s to get the speed of the first place. Then add 80 to this to get the speed of the second.

Answer 2

The first equation has 3 variables. You need at least 3 equations to solve it. Therefore, as is, it is unsolvable.

Let S equal the speed of airplane #1. Then S + 80 equals the speed of airplane #2.

The combined speed of the 2 planes is:
S + S + 80 = 2S + 80

They travel for 3 hours at the combined speed of 2S + 80 so:

(3)(2S + 80) = 2940

Thus, 6S + 240 = 2940

Thus, 6S = 2940 - 240 = 2700

Thus, S = 2700/6 = 450 miles per hour for plane #1

The speed for plane #2 is S + 80, thus,
450 + 80 = 530 mph

Hope this helps. Good luck.

Answer 3

2y - a/3 = a + 3b/4
You have three variables and one equation. You can't solve this. Please check the questions again.

One airplane speed = x
the other airplane speed is x +80

They are traveling in opposite directions so add their speed together.

3 (x + (x+80) = 2940

3(2x+80) = 2940

6x + 240 = 2940

6x = 2700

x = 450 mph

Plane 1 = 450 mph
Plane 2 = 450 mph + 80 mph = 530mph

Answer 4

2y -a / 3 = a + 3b / 4

Note: LCD is 12.

Therefore multiply both fractions by 12.

8y - 4a = 3a + 9b; if you want to solve for a:

add 4a to both sides: 8y = 12a + 9b

subtract 9b on both sides: 8y - 9b = 12a

now divide by 12: 8y - 9b / 12 = a; if you need to solve for another variable just do the same but for that variable.

Sorry but i don't like word problems!