HW3 - Solution to HW 3 Ning SUN August 6 2009 5.1 6 18(a 22...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Solution to HW 3 Ning SUN August 6, 2009 5.1: 6, 18(a), 22, 32; 5.2: 4, 10, 14, 16 (b, c, d) , 25, 32, 38 5.1#6 n ( n- 1) 5.1#18 • (a) The letters can appear rst or last, 2 ways. The number of ways of choosing 3 letters, repetition allowed and order is important is 26 3 , similarly 3 number 10 3 , so the answer is 2 · 26 3 · 10 3 = 35 , 152 , 000 ways. 5.1#22 The rst digit has 3 choices, each of the following digits has only 2 choices (they cannot be the same as the previous digit), so we have 3 · 2 9 = 1536 ways. 5.1#32 There are three overlapping letters: R, E and N. 10 letters in RECURRENCE , and 8 letters in RELATION . #(total outcomes)= 10 · 8 = 80 . #(desired outcomes)=(RR+EE+NN)= 3 · 1 + 3 · 1 + 1 · 1 = 7 . So the requested probability is 7 80 = 0 . 0875 . 5.2#4 1. Seating 4 di erent girls and 4 di erent boys at a long table is equivalent to having the 8 kids stand in line, so there are 8! = 40 , 320 ....
View Full Document

This note was uploaded on 08/30/2010 for the course AMS 301 taught by Professor Arkin during the Spring '08 term at SUNY Stony Brook.

Page1 / 2

HW3 - Solution to HW 3 Ning SUN August 6 2009 5.1 6 18(a 22...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online