probability that exactly 5 customers pay in cash is 0.178863
Total number of customer = 20
probability of payment in cash = 0.3
probability of payments via other methods = 1 - 0.3 =0.7
let probability of payment in cash be p
and probability of payments via other methods be q
To find the probability that exactly y customers pay in cash
p [ x = y ] = [tex]n_c__x p^x q ^(n-x)[/tex]
here value of y= 5 and n=20 , p =0.3 , q= 0.7
putting the values in above equations we get:
p [ x =5 ] = [tex]20_c__5 * 0.3 ^5 * 0.7 ^15[/tex]
p [ x =5 ] = (15504) * (0.00243) * (0.0047475615)
p [ x =5 ] = 0.178863
so the probability that exactly 5 customers pay in cash is 0.178863
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