Question 424111: Can you please check my answer Thanks
4. An identification code is to consist of seven letters followed by three digits. How many different codes are possible if repetition is permitted? (Points : 2)
26 is the number in the alphabet 10 is the number from 0-9 26^7*10^3= 8031810176*1000=8031810176000 different codes
5. Show all work. A disc jockey has 10 songs to play. Seven are slow songs, and three are fast songs. Each song is to be played only once. In how many ways can the disc jockey play the 10 songs if
• The songs can be played in any order. The 1st is 1 of 10, then 1 of 9, 8, 7 etc
= 10*9*8*7... = 10!
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* The first song must be a slow song and the last song must be a slow song.
The 1st is 1/7, the last is 1/6. The other 8 are 1 of 8, 7, 6, 5, 4,The first song must be a slow song and the last song must be a slow song. The 1st is 1/7, the last is 1/6. The other 8 are 1 of 8, 7, 6, 5, 4, 3, 2, 1= 7*6*(8!)
• The first two songs must be fast songs. 3*2*(8!)
(Points : 3)
Answer by sudhanshu_kmr(1152)   (Show Source):
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