In a bag with plastic shapes, there are 6 triangles, 4 circles, and 5 squares. What is the probability of pulling out two triangles if the first shape is replaced before the second shape is pulled out? Write your answer as a simplified fraction.
The probability of pulling out a triangle on the first draw is 6/15 since there are 6 triangles out of 15 total shapes.
Since the shape is replaced before the second draw, the probability of pulling out another triangle on the second draw is also 6/15.
To find the probability of both events occurring, we multiply the probabilities: (6/15) * (6/15) = 36/225.
We can simplify this fraction by dividing the numerator and denominator by their greatest common factor, which is 9. Simplifying gives us 4/25.
Therefore, the probability of pulling out two triangles if the first shape is replaced before the second shape is pulled out is 4/25. Answer: \boxed{\frac{4}{25}}.