If a carton containing a dozen mirrors is dropped, which of the following
cannot be the ratio of broken mirrors to unbroken mirrors?
(a) 2: 1
(b) 3: 1
(c) 3: 2
(d) 7 : 5
Since the total number of mirrors is mentioned as 12 (Dozen) it has to be completely divisible by the ratio.
Example : 7+5=12 , 3+1=4 ,2+1=3 but not 3+2=5.
Hence the solution is D.