Question 1157861

Christine drives her car 495 miles and has an average of a certain speed. If the average speed had been 2mph more, she could have traveled 517 miles in the same length of time. What was her average speed?
<pre>Doesn't have to be as complex, and with large numbers as the other person would have you believe.

Let the speed be S
Then we get the following TIME equation: {{{matrix(1,3, 495/S, "=", 517/(S + 2))}}}
{{{matrix(1,3, 45/S, "=", 47/(S + 2))}}}  ------ Reducing the fractions by factoring out the numerator-GCF, 11
47S = 45(S + 2) ------- Cross-multiplying
47S = 45S + 90
47S - 45S = 90
2S = 90
Average speed or {{{highlight_green(matrix(1,6, S, "=", 90/2, "=", 45, mph))}}}