A Long Journey of 27000 Miles

The MacDonalds are planning a long car journey of 27,000 miles. If they use tires that last 12,000 miles each, how many tires will they need, and how can they make the best use of them?

This is how usage of tires can be optimized!

Optimizing The Use of Tires in Long Journey!

How long the actual journey is?

Since each tire would be traveling 27,000 miles, when car travels 27000 miles; tire -miles are equal to 27000 x 4 = 108000.

But the each tire lasts for 12000 then tires required = 108000/ 12000 = 9.

Now managing use of these 9 tires need some planning.

For first 12000 miles of 27000 miles they can use 4 out of 9 tires. For the rest of 15000 miles use of remaining 5 tires need to be planned.

Best way is to change 1 tire after every 3000 miles like below.

First 3000 miles: Tires 1, 2, 3, 4

Second 3000 miles: Tires 2, 3, 4, 5

Third 3000 miles: Tires 3, 4, 5, 1

Fourth 3000 miles: Tires 4, 5, 1, 2

Fifth 3000 miles: Tires 5, 1, 2, 3

This way, it's made sure that each tire is used for only 12000 miles. And this is how the journey can be completed using 9 tires only.