Answer:
A
Step-by-step explanation:
distributive property
Since there is no repetition allowed, there are 10 possibilities for the 1st digit, 9 for the 2nd, 8 for the 3rd, and 7 for the 4th. This gives a total of (10)(9)(8)(7) = 5040 four-digit codes.
For all odd digits to be used, there are 5 possibilities for the 1st digit (1,3,5,7,9), 4 for the 2nd, 3 for the 3rd, 2 for the 4th. This gives a total of (5)(4)(3)(2) = 120 codes that only use odd digits.
Therefore there are 5040 - 120 = 4920 codes that do not consist of all odd digits. The probability is 4920/5040 = 41/42.
3(x+y)=y
y is not equal to zero
*Solution
1. The given equation is 3(x+y) = y and we are tasked to find the ratio between x and y. Distributing 3 to the terms in the parenthesis,
3(x+y) = y
3x + 3y = y
Transposing 3y to the right side OR subtracting 3y from both the left-hand side and the right-hand side of the equation would give
3x = -2y
Dividing both sides of the equation by 3,
x = (-2/3)y
Dividing both sides of the equation by y,
x/y = -2/3
Therefore, the ratio x/y has a value of -2/3 provided that y is not equal to zero.
