Tickets are numbered from 1 to 10. Two tickets are drawn one after the other art random. Find the probability that the number on one of the tickets is a multiple of 5 and on the other a multiple of 4.

Explanation

It is known that 5 and 10 are multiples of 5 , while 4 and 8 are multiples of 4 .

P( multiple of 5)`=frac{2}{10}=frac{1}{5}`
P( multiple of 4)`=frac{2}{10}=frac{1}{5}`

P ( multiple of 5 and multiple of 4)=P ( multiple of 5 on first card and multiple of 4 on second card)
+P ( multiple of angle on first card and multiple of 5 on second card)

`=frac{2}{10} times frac{2}{9}+frac{2}{10} times frac{2}{9}`

[ Without replacement ]


`=frac{4}{90}+frac{4}{90}`

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