Let's say the pet shop has k kittens.
Since there are 2 puppies, the total number of animals in the pet shop is 2 + k.
The cost of the puppies is 2 * $20 = $40.
The cost of the kittens is k * $15 = $15k.
The total value of the stock is $100.
So, we have the equation $40 + $15k = $100.
Subtracting $40 from both sides of the equation, we get $15k = $60.
Dividing both sides of the equation by $15, we get k = $60 / $15 = 4.
Therefore, the pet shop has 4 kittens.
#### 4
The answer is: 4
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
A pet shop has 2 puppies and some kittens. A puppy costs $20, and a kitten costs $15. If the stock is worth $100, how many kittens does the pet shop have?

### Answer:
