A car traveled 75% of the way from town A to town B at an average speed of 80 miles per hour. The car travels at an average speed of S miles per hour for the remaining part of the trip. The average speed for the entire trip was 40 miles per hour. What is S ?  Choose the correct choice from the following answers.
A) 16
B) 20
C) 25
D) 30
E) 37.5
Total distance = 100 miles (easier to work with %)   75% of the distance = 75 miles   25% of the distance = 25 miles   1st part of the trip →  75/80= 
<gadget id="calculator"> 75/80</gadget>
<output>15/16 = around 0.9375</output>
0.9375   2nd part of the trip → 25/S= t   Total trip → (75+25)/40 = 0.9375 + t » 100/40 = 0.9375 + t » 2.5 = 0.9375 + t » t = 1.5625   Back to 2nd part of the trip formula: 25/S = 1.5625 » S = 16   16ns 16
<result>A</result>
A car traveled 75% of the way from town A to town B at an average speed of 80 miles per hour. The car travels at an average speed of S miles per hour for the remaining part of the trip. The average speed for the entire trip was 40 miles per hour. What is S ?