<h3>
Answer: D) 1/24</h3>
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Explanation:
There are 4 digits to pick from and 4 slots to fill, so there are 4! = 4*3*2*1 = 24 different codes possible.
If we want the code to start with 371, then that must mean 5 is the only thing left for that fourth slot. In short, there's only one code that starts with 371 and that code is 3715
We have one code we want (3715) out of 24 total, which is why the answer is 1/24 (choice D)
I am confident that the best option is Last one in this case.
For this case we must solve a system of two equations with two unknowns, given by "x" and "y".
We have:
We multiply (2) by -1:
We add (1) and (3):
Clearing x:
We substitute 
in (2)
Thus, the solution of the system is 
Answer:
The solution of the system is
