Question

A train consists of 36 carriages. There were 1,400 passengers on the train. In every ten consecutive carriages, there will be 398 passengers How many passengers occupy 4 middle carriages of the train ?​

Answer 1

4 middle carriages have 162 passengers

Explanation:

Since every 10 consecutive carriages have 398 passengers, then each carriage has 398/10 = 39.8 passengers.

Since there are 36 carriages in the train, then there are 36 * 39.8 = 1428 passengers in the train.

Therefore, there are 1400 - 1428 = -28 passengers missing.

This means that each carriage has 39.8 - (-28/36) = 39.8 + 0.78 = 40.58 passengers.

So, the 4 middle carriages have 4 * 40.58 = 162.32 passengers.

Rounding to the nearest whole number, we can say that 4 middle carriages have 162 passengers.

Answer 2

192

Explanation:

If a train with 36 carriages holds 1400 passengers, 398 in any 10 consecutive carriages, you want to know the number in the 4 middle carriages.

Model

The first 30 carriages will hold 3·398 = 1194 passengers, so there must be 1400 -1194 = 206 in the remaining 6 carriages. The same would be true counting carriages from the other end.

Then the 10 +6 carriages at either end of the train must hold 398 +206 = 604 passengers. That leaves 1400 -2·604 = 192 passengers in the middle 4 carriages.