Question 945044
The probability of an account having less than $1000 is 
{{{P=21/41}}}
So the probability of an account having at least $1000 is 
{{{P=1-21/41=41/41-21/41=20/41}}}
.
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Choosing 5 at random and having exactly 4 at least $1000 (Y) and 1 less than $1000 (X), gives you 5 possible outcomes. 
XYYYY
YXYYY
YYXYY
YYYXY
YYYYX
So then the probability would be,
{{{P=5*(20/41)^4*(21/41)}}}
{{{P=5*.0566*0.5122}}}
{{{P=0.145}}}