A car traveled 75% of the way from town A to town B at an average speed of 60 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 answer:
A) 10
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 →  75/60= 
<gadget id="calculator"> 75/60</gadget>
<output>5/4 = around 1.25</output>
1.25   2nd part of the trip → 25/S= t   Total trip → (75+25)/40 = 1.25 + t » 100/40 = 1.25 + t » 2.5 = 1.25 + t » t = 1.25   20ack to 2nd part of the trip formula: 25/S = 1.25 » S = 20   Ans 20
<result>B</result>
A car traveled 75% of the way from town A to town B at an average speed of 60 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 ?