Carcass wrote:
Jan and Marko are competing in an off-road race. Jan completes 3/4 of the race in 2 hours. Marko completes 2/3 of the race in 5/8 of the time it takes Jan to complete 9/10 of the race.
Quantity A |
Quantity B |
Jan’s rate |
Marko’s rate |
A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
Kudos for the right answer and explanation
Let d = the TOTAL distance of the race
Jan completes 3/4 of the race in 2 hoursDistance traveled = (3/4)(d) = 3d/4
Speed = distance/time = (3d/4)/2
= 3d/8
So, Jan's speed = 3d/8
Marko completes 2/3 of the race in 5/8 of the time it takes Jan to complete 9/10 of the raceWe already know that Jan's speed = 3d/8
9/10 of the race distance = 9d/10
Time it takes Jan to complete 9/10 of the race = distance/speed = (9d/10)/(3d/8) = (9d/10)(8/3d) = 72d/30d = 72/30 = 12/5 (hours)
5/8 of 12/5 = (5/8)(12/5) = 60/40 = 3/2
So, it takes Marko 3/2 hours to complete 2/3 of the race
2/3 of the race distance = 2d/3
Speed = distance/time = (2d/3)/(3/2)
= (2d/3)(2/3)
= 4d/9
So, Marko's speed = 4d/9
We get:
QUANTITY A: 3d/8
QUANTITY B: 4d/9
Multiply both quantities by 72 to get:
QUANTITY A: 27d
QUANTITY B: 32d
Answer: B
Cheers,
Brent