Pat traveled a distance of 240 miles in x hours. For a part of journey he was travelling at constant speed of 40 miles per hour whereas for the remaining part of the journey he was traveling at constant speed of z miles per hour. How long was he traveling at z miles per hour.
(1) Average speed for the journey is 48 miles per hour. (Total time)=(Total distance)/(Average Speed), thus this statement implies that (Total time)=x=240/48=5 hours. So, we have that zt+40(5-t)=240 --> zt+200-40t=240 --> t(z-40)=40. Not sufficient.
(2) z > 48 miles per hour. Clearly insufficient.
(1)+(2) We have that t(z-40)=40 and z>48. Still insufficient to get t.
Answer: E.
(1) Average speed for the journey is 48 miles per hour. (Total time)=(Total distance)/(Average Speed), thus this statement implies that (Total time)=x=240/48=5 hours. So, we have that zt+40(5-t)=240 --> zt+200-40t=240 --> t(z-40)=40. Not sufficient.
(2) z > 48 miles per hour. Clearly insufficient.
(1)+(2) We have that t(z-40)=40 and z>48. Still insufficient to get t.
Answer: E.