im in highschool and i have no idea
Step-by-step explanation:
3 digits, there are 10 digits: 0, 1, ..., 9. Order matters 123 is a different code than 321, then
Possible codes: 10 * 9 * 8 = 720, since it can not be repeated.
If he chooses one code:
P = 1 / 720 = 0.138 %
Probably, 1/720 is the best way to write the answer since it shows what it means.
First it would be 10/120
then to make it into its simplest form you would divide by 10 so:
1/12
So sum means add
difference means subtract
represent as x and y
x+y=55 times (x-y)
find ratio of numbers
solve for one placeholder and simplify
solve for y
distributiver property a(b-c)=ab-ac
55(x-y)=55x-55y