On a certain trip, John spent 2 hours at 50mph, 2 hours at 55mph, and

Question

On a certain trip, John spent 2 hours at 50mph, 2 hours at 55mph, and 2 hours at 60mph. What was his average speed for the trip?

A. 51 
 B. 45.5 
 C. 58.5 
 D. 55 
 E. 67

This is a  PS Butler Question

Check the links to other Butler Projects:

Data Sufficiency Butler  
  Critical Reasoning Butler  
  Sentence Correction Butler  
  Reading Comprehension Butler  
  Integrated Reasoning Butler

satish_sahoo · Answer

Avg speed = Total distance/Total time

1st part -> 2hrs @50mph = 100 miles (time*speed)
2nd part -> 2hrs @55mph = 110 miles (time*speed)
3rd part -> 2hrs @60mph = 120 miles (time*speed)

Total dist of trip = 100+110+120 = 330 miles
Total time taken = 2+2+2 = 6 hrs

Avg speed =  \frac{330}{6} = 55 mph

I think D.

Hope it helps.

Abdelaali91 · Answer

average speed = total distance/total time=(50*2+2*55+2*60)/(2+2+2)=330/6=55 mph

Answer D

Ayeka · Answer

Average speed= Total distance/Total time
Average Speed= (T1*S1+T2*S2+T3*S3)/(T1+T2+T3)
 = (2*50+2*55+2*60)/(2+2+2)
 = 330/6= 55 mph

Answer: D

prantorboni · Answer

On a certain trip, John spent 2 hours at 50mph, 2 hours at 55mph, and 2 hours at 60mph. What was his average speed for the trip?

Entire distance, 2x50=100, 2x55=110 & 2x60=120, Total= 100+110+120=330
 Total time: 6, Average Speed= 330/6= 55mph.

Answer: D.

ManifestDreamMBA · Answer

Since these are equal weights, we can just consider the avg of 50,55 and 60. These values are in AP, so the avg is 55

Prep Toolkit