y = kx
'k' is the constant of proportionality, or otherwise known as constant of variation.
y = 90
x = 3
90 = k(3)
90 = 3k
3k/3 = 90/3
k = 30
The constant of proportionality is 30.
9 of them are puppies because 15 percent of 60=9
The answer is equal to 300.
Answer:

Step-by-step explanation:
Let us first find the number of possible credit card numbers that can be formed with the numbers 0 - 9.
We want to form a 16 digit number out of 10 digits, so, we have:

There are
numbers that can be formed.
There are only 100 million valid numbers (
). Let the number of valid numbers be n.
Therefore, the probability of picking a number that is valid is:
P(valid) = n / N

No rational needs to be writing in decimal form not fraction