Puzzle:
A car has 4 tyres and 1 spare tyre. Each tyre can travel a maximum distance of 20000 kilometers before wearing off. What is the maximum distance the car can travel. You are allowed to change tyres (using the spare tyre) unlimited number of times.
Note: All tyres are used upto their full strength.
Puzzle Solution:
25000
Divide the lifetime of spare tire into 4 equal part i.e., 5000 and swap it at each completion of 5000 Kms distance.
Let four tyres be A, B, C and D and spare tyre be S.
5000 KMs: Replace A with S.
10000 KMs: Put A back to its original position and replace B with S
15000 KMs: Put B back to its original position and replace C with S
20000 KMs: Put C back to its original position and replace D with S
What if car we have 5 tyres i.e. including extra type of stepney..?? what will be answer in that case??
hello my name is hasafesus and i really need help it always says CYKA BLAYT ISNT WORKING I CRY EVERYDAY please help
Thank you
answer is 25000 KMS
Divide the distances in 5000 kms zones
Use 1 to 4 tyres for 5000
Then change 1st tyre by spare drive 5000
Now tyre 2 3 4 have travelled 10000 while 1 and S only 5000
Change 2nd by 1 travell 5000
Now 3 4 have travelled 15000 while rest only 10000
Now change 3rd by 2 travel 5000
Now 4 travelled 20000 and is wear out while others have travelled only 15000
So change 4 by 3 now travel 5000
So total distance travelled 25000km
How to prove that 25k is the maximum distance??
u see we are not using the spare tire for the first (limit)/(number of tires not including the spare) km and after that, we are replacing rest but 1 tire with spare and finally replacing the dead tire with spare, and now all the tires present can run for (limit)/(number of tires not including the spare) km.
Eg. 3 wheels + 1 spare, limit 120km
the maximum distance will be = limit+(limit/number of tires)=120+40=160km