Puzzle 29 | (Car Wheel Puzzle)

A car has 4 tyres and 1 spare tyre. Each tyre can travel a maximum distance of 20000 miles before wearing off. What is the maximum distance the car can travel before you are forced to buy a new tyre? You are allowed to change tyres (using the spare tyre) unlimited number of times.









Answer: 25000

Divide the lifetime of spare tire into 4 equal part i.e., 5000 and swap it at each completion of 5000 miles distance.

Let four tyres be A, B, C and D and spare tyre be S.

5000 KMs: Replace A with S. Remaining distances (A,B,C,D,S) : 15000,15000,15000,15000,20000
10000 KMs: Put A back to its original position and replace B with S. Remaining distances (A,B,C,D,S) : 15000,10000,10000,10000,15000
15000 KMs: Put B back to its original position and replace C with S. Remaining distances (A,B,C,D,S) : 10000,10000,5000,5000,10000
20000 KMs: Put C back to its original position and replace D with S. Remaining distances (A,B,C,D,S) : 5000,5000,5000,0,5000
25000 KMs : Every tyre is now worn out completely.

All tyres are used upto their full strength.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above



My Personal Notes arrow_drop_up

Improved By : Gurjeet Singh 2



Article Tags :
Practice Tags :


4


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.