CFA Practice Question

There are 410 practice questions for this study session.

CFA Practice Question

How many three-digit numbers can you form using the digits 1, 3, 5, 7, and 9 if you are allowed to repeat any of the aforementioned digits any number of times within the number to be formed?
A. 20
B. 60
C. 125

User Contributed Comments 9

User Comment
Menzies 5x5x5=125
Because u can reuse the numbers
CocaColas Is there any more theoretical way to get to the answer other than by doing it manually?
mtcfa Any five digits can be used in slot 1, any five digits can be used in slot 2, and any five digits can be used in slot 3... hope that helps.
labsbamb ok good
rahul1983 The number in the first place can be picked up in 5 ways. Similiarly for secon and the third place.
Now to form a three digit number, you'll have to pick (number1 AND number2 AND number3). The pick of numbers is mutually exclusive to each other since repetitions are allowed. Hence the answers 5*5*5 = 125
P.S: I got the answer incorrect coz I failed to recollect my permutation and combination fundamentals
cslau83 why can't we do a straight permutation calculation to get 60?
Shaan23 When you do permutation the numbers are not reused again. Only can use the numbers once then
sandk024 On the BAII you can use 5! by entering 5[2nd][x!] = 120 + 5 because the numbers are allowed to be repeated.
kmurdoch Why is it +5 sandko24?
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