The half lives of radioactive elements `X` and `Y` are `3` minute and `27` minute respectively. If the activities of both are same, then calculate the ratio of number of atoms of X and Y.

Explanation

`A_(1) = lambda N_(1)`
`" and " A_(2) = lambda N_(2)`
` A_(1)= A_(2) r .(0.693)/( T_(1)) N_(1) = (0.693)/( T_(2)) N_(2) r (N_(1))/( T_(1)) = (N_(2))/( T_(2))`
`r .(N_(1))/(N_(2)) = (3)/( 27) = (1)/(9) N_(1) : N_(2) 1:9`