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An integer is chosen at random from the integers 1,2,3, ,50. The probability that the chosen integer is a multiple of at least one of 4, 6 and 7 is
(4) 2150
A, B, C: multiples of 4, 6, 7 in 1 to 50
n( A)=12, n( B)=8, n( C)=7
n( A B)=4 (multiples of 12), n( B C)=1 (of 42)
n( A C)=1 (of 28), n( A B C)=0 (of 84)
∵ Inclusion–exclusion:
n( A B C)=(12+8+7)-(4+1+1)+0=21
P= 2150
Answer: (4)
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