Math question?

Question

John is walking east at a speed of 3 miles per hour, while Bob is also walking east, but at a speed of 5 miles per hour. If Bob is now 1 mile west of John, how many minutes will it take for Bob to catch up to John?

Answer 1

In order to catch up to John, Bob must walk 1 mile farther in the same amount of time. Because Bob's speed exceeds John's speed by 5 - 3 = 2 miles per hour, the time required for Bob to catch up to John is 1/2 hour, which is 30 minutes.

Answer 2

48 minutes.

John will walk 3 miles, or 15,840 feet in one hour.

Bob will walk 5 miles, or 26,400 feet in one hour.

John is 5280 feet ahead, meaning that John will have a total distance covered of 21,120 feet.

In the meantime, Bob will walk the 21,120 feet (4 miles) in 48 minutes <4 miles is 80% of Bob's speed>

80% of 1 hour is 48 minutes.

The answers comparing Bob and John's distance neglect to identify one fact - since each person is traveling different rates, both will not have the same distance. You need to bring distance to a common point of reference. Conversion to feet, and adding the mile difference they are as time starts, gives a commonpoint to refer to.

Answer 3

By data we know the difference of distances between John (J) and Bob (B) of one mile:

B = J + 1 .................(1) also we know that velocity = space/time

V = S/T
Vj = 3 my/hr and Vb = 5mi/hr
Then we Replace values in (1) : T = unknown

5T = 3T + 1 Resolving this equation we obtain:
T=1/2 hour= 30 minutes

Answer 4

At first this looked like a SAT or IQ question
There is no a2 +b2=c2
They are both walking in the same direcion at a difference of 2 mph , they are a mile apart
The easy answer is 1 hour

Answer 5

note
d = rt

when they meet, john will walk d (distance)
and Bob will have walked d + 1

john d = 3t
bob d + 1 = 5t
bob d = 5t - 1

since d = d, then
3t = 5t - 1
subtract 3t from both sides
0 = 2t - 1
add 1 to both sides
2t = 1
t = 1/2 hour

Answer 6

3t+1 = 5t
2t = 1
t = 1/2hour

Answer 7

Half an hour. The closure rate is two mph.