Question

A box contains 4 yellow tiles, 6 green tiles, and 10 purple tiles. Without looking, you draw out a tile and then draw out a second tile without returning the first tile. Find P(purple, then purple)

Answer 1

4 yellow + 6 green + 10 purple = 20 total tiles

1st draw P purple: 10 purple/20 total
2nd draw P purple: 9 purple/19 total

Probability purple then purple (no returns): $\frac{10}{20} x \frac{9}{19}$
= 90/380
= 45/190
= 9/38