SOLUTION: Jim traveled 240 miles to a convention. Later, his wife Ann drove up to meet him. Ann's average speed exceeded Jim's by 4 mph, and the trip took her 15 minutes less time. Find Ann'

Question 606313: Jim traveled 240 miles to a convention. Later, his wife Ann drove up to meet him. Ann's average speed exceeded Jim's by 4 mph, and the trip took her 15 minutes less time. Find Ann's speed.
Answer by vksarvepalli(154) (Show Source): You can put this solution on YOUR website!
Let the average speed of Jim be 'x' mph
so the average speed of Ann will be 'x+4' mph
let time taken by Jim to travel is 't' hrs.
then the time taken by Ann will be 't-0.25' hrs. (Since 15 mins = .25 hrs)
Now, average speed = total distance travelled / total time taken.
so, x = 240/t --- eq.1
x+4 = 240/(t-0.25) -----eq.2

Substituting eq.1 in eq.2

we get (240/t) + 4 = 240/(t-0.25)
=> 1/t + 1/60 = 1/(t-0.25)
=> 1/(t-0.25) - 1/t = 1/60
=> 4t^2-t-60 = 0
So t= 4 or t= -15/4
since time cannot be a negative value.
t = 4 hrs.
from eq.1 x = 240/t = 240/4 = 60 mph
So, Ann's speed = x+4 = 60+4 = 64 mph
Ans: 64 mph
RELATED QUESTIONS
Jim is taking a canoe in the Grand River. The speed of the current is 3 miles per hour.... (answered by josgarithmetic,MathTherapy,ikleyn)

Jim drove the 120 miles to Grandmother's house in 3 hours. He increased his speed by 10... (answered by solver91311)

Jim drove the 120 miles to Grandmother's house in 3 hours. He increased his speed by 10... (answered by Alan3354)

Traffic reduces Jim�s usual speed by 10mph, which lengthened his 200mph trip by 1 hour.... (answered by Alan3354)

Jim drove a total of 200 miles on a trip to visit his parents. The return route was 8... (answered by solve_for_x,ikleyn)

Along a road, spot X and spot Y are 1150m apart. Ann walks along the road from X to Y at... (answered by josgarithmetic)

ann and bob move towards eachother along a straight road. Ann goes with a constant speed... (answered by solver91311)

Jim is a paratrooper who has to land on a moving aircraft carrier. If his plane is flying (answered by josmiceli)

Solve: Jim drove 196 miles in 4 hours. If he can keep the same pace, how long will it... (answered by checkley77)