X | Y
-2 | 9
-1 | 6
0 | 3
1 | 0
2 | -3
Answer:
Step-by-step explanation:
Total number of antenna is 15
Defective antenna is 3
The functional antenna is 15-3=12.
Now, if no two defectives are to be consecutive, then the spaces between the functional antennas must each contain at most one defective antenna.
So,
We line up the 13 good ones, and see where the bad one will fits in
__G __ G __ G __ G __ G __G __ G __ G __ G __ G __ G __ G __G __
Each of the places where there's a line is an available spot for one (and no more than one!) bad antenna.
Then,
There are 14 spot available for the defective and there are 3 defective, so the arrange will be combinational arrangement
ⁿCr= n!/(n-r)!r!
The number of arrangement is
14C3=14!/(14-3)!3!
14C3=14×13×12×11!/11!×3×2
14C3=14×13×12/6
14C3=364ways
Multiplying by 10 can be thought of as just adding a 0 to the right end of a number. If you have 2 and multiply it by 10, you get 20. For 1,234, you get 12,340. If you have 98,765, you can 987,650. Same thing applies for 100, 1000, 10000, ...., and so on. It moves it over depending on the number of 0's there are in the number. If it is 100, it will move two 0's over. For example, if you multiply 45 by 100, you get 4,500. The two zeros from 100 moved to the right side of the 45 to get 4500.
It is systematic because they are going every tenth person, in a random manner.
