There are 
ways of picking 2 of the 10 available positions for a 0. 8 positions remain.
There are 
ways of picking 3 of the 8 available positions for a 1. 5 positions remain, but we're filling all of them with 2s, and there's 
way of doing that.
So we have
The last expression has a more compact form in terms of the so-called multinomial coefficient,
Hi there,
2400 + 1632 = 4032
3 * 192 = 576
4032 - 576 =>
3532 - 76 =>
3532 + 24 - 76 - 24
3556 - 100
3456
3456 / 576 => 6
Therefore, 6 hours of sprayer work
Hope this helps!
Sincerely,
Dus4nR
