How many different arrangements of letters are possible if three letters are chosen from the letters A through E and the letters E and A must be among the letters selected? Select.
A) 72 B) 64 C) 36 D) 18 E) 6
Since A and E must be among 3 letters then the third letter must be out of B, C and D. 3C1 = 3 ways to choose which one it'll be. Now, 3 different letters (A, E and the third one) can be arranged in 3!=6 ways, so the final answer is 3*6= 
<gadget id="calculator">3*6</gadget>
<output>18</output>
18.   Answer: 18.
<result>D</result>
How many different arrangements of letters are possible if three letters are chosen from the letters A through E and the letters E and A must be among the letters selected?