Uhhh, kind of an estimated guess but I got $7426.30
If the car can travel 81 km in one hour, (60 minutes) that means that it can travel 81/60 in a minute. The result is 1.35, and this times 15 will give you the amount the car can travel in 15 minutes. The answer is 20.25km
You originally start out with 28 marbles. each marble has a number out of 28 to create a percentage. 21/28 or 75% signifies red, 4/28 or about 14% is white and 3/28 or about 11% is gray. add white and gray, which is 7/28 combined or 25% together. multiply by number of times the process is completed, which is 112 and the final answer is 28
2/7 because its a part to whole ratio.