The numbers are "x" and "y",
we suggest this system of equations.
x+y=24
x-y=15
solve by reduction method.
x+y=24
x-y=15
-----------------
2x=39 ⇒x=39/2=19.5
x+y=24
-(x-y=15)
-------------------
2y=9 ⇒y=9/2=4.5
The numbers are 19.5 and 4.5
To check
19.5+4.5=24
19.5-4.5=15
If the average rates were 20 and 25 miles per hour, then together they cover 45 miles of the distance they are separated by per hour. The ships will be 30 miles apart when 270 miles have been covered, so it takes 270/45=6 hours to cover the distance. 6 hours after 5 PM is 11:00 PM.
It is 0.7p= p-250. 0.7p represents the tv with a 30% discount and p-250 represents the tv with a $250 discount.
Combine like-terms
-2.1x and 4.9x = 2.8x
3.7 and 5 = 8.7
2.8x + 8.7 is your final answer.