Answer: 720 ways
Step-by-step explanation:
Given
A train has 1 main engine and remaining 6 train cars
If the engine is always in the front the remaining train cars can be arranged is
270.1666666666667 this is the anwser
6x + 2x - 1 = 5x + 11
8x - 1 = 5x + 11
- 5x - 5x
3x - 1 = 11
+ 1 + 1
3x = 12
3 3
x = 4
243.87 and 132.37 thts the answer