a there is a 1 in 108 chance that he will roll three vowels
b there is a 1 in 216 chance that he will roll the word dip
Step-by-step explanation:
a there is a 2/6 chance of rolling a vowel on the first die, and a 1/6 chance of rolling a vowel on the 2nd and 3rd dice. Multiply these together and you have 1/108.
b there is a 1/6 chance of rolling the letter D on the first die, 1/6 chance of rolling I on the second, and 1/6 chance of rolling P on the third. Multiply these together and you have 1/216.