Question 1149233
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Using algebra....<br>
Let the speeds be x and x+40.  Then<br>
{{{4(x)+4(x+40) = 2160}}}<br>
Solve using basic algebra....<br>
Using logical analysis and simple mental arithmetic....<br>
The combined speed is 2160/4 = 540.
If the two speeds were the same, they would each be 270; 270+270=540.
To get two speeds that differ by 40mph, add 20mph to one speed and subtract 20mph from the other.<br>
ANSWER: 270+20 = 290mph and 270-20 = 250mph<br>
CHECK:
{{{4(290)+4(250) = 1160+1000 = 2160}}}<br>