Practicing Success
Three numbers are selected simultaneously from the set {1, 2, 3, …., 25}. The probability that the product of selected numbers is divisible by 4, is equal to |
$\frac{1}{115}$ $\frac{98}{115}$ $\frac{773}{1150}$ $\frac{963}{1150}$ |
$\frac{773}{1150}$ |
Product can’t be divisibly by 4 in the following mutually exclusive cases; (i) All the selected numbers are odd. corresponding ways = ${ }^{13} C_3=286$ (ii) Two of the selected numbers are odd and another is a multiple of 2 only. Corresponding ways = ${ }^{13} C_2 . { }^6 C_1=468$ Thus, required probability $=1-\frac{(286+468)}{{ }^{25} C_3}=\frac{773}{1150}$ |