Answer:
658,008
Explanation:
We need to make different groups of 35 cars out of 40 cars.
We will choose 35 cars from 40 cars.
Here we will use combination because arrangement doesn't matter.
If we choose a card for group the it might be any order.
either one 1st, 2nd .. or 10th .
It should be same group.
So, Combination of nCr(40,35)
Total number of different groups:

Hence, The total 658,008 different group of 35 cars can be formed.