Find n if C(n, 3) = P(n, 2)

When you have 25 numbers, and jake picks 3 random numbers and puts them back, what is the chance bob has of picking those 3 numbers when he picks 6 random numbers (without putting them back)? explain.

Cone a has a surface area of 384 ft2 and cone b has a surface area of 96 ft? . what is the ratio of their volume?

Which image (a’ b’ c’ d’) of abcd cannot he produced using only reflections ?