algebra 1 problem solving

Question

the sum of the speeds of two trains is 724.1 mph if the speed of the first train is 5.9 mph faster than the second train find the speeds for each

Answer 1

Let Train 1= X

Let Train 2= X + 5.9

Note: Since we see the word sum we know that we must add them together and that their totals have to equal to 724.1.

X + X+ 5.9 = 724.1

Add like terms

2X + 5.9= 724.1

Subtract 5.9 from each side

2X+5.9= 724.1

-5.9. 5.9

--------------------

2X = 718.2.

Note: Make sure to line up the numbers correctly when working with decimals.

Since we want to solve for X we need to isolate it. Therefore, we must divide both sides by 2.

2X= 718.2

--- ------

2 2

X= 359.1

Now, we have the speed for Train 1 (359.1 mph). Next, we have to add 5.9 to find the speed for Train 2.

359.1

+ 5.9

--------

365.0

Therefore, the speed for Train 2 is 365 mph.

To check the answer we must add 359.1 and 365 together.

359.1

+365.0

----------

724.1

Answer 2

X + (X+5.9) =724.1

2X + 5.9 = 724.1

2X = 718.2

X = 359.1 mph

359.1 + 5.9 = 365 mph

The two trains are going 359.1 mph and 365 mph, respectively.