There are 18 black-and-white photos in the album if there are 90 photos in the album with fraction of the photos are black and white

18/90 or you can say 18 over 90.

Step-by-step explanation:

So we have 18 out of the total of 90 photos.

So we know automatically the fraction is 18/90, we have 18 out of the rest of the 90 photos.  

since proposition states that a number is greater than 25, if is true then the number must actually be greater than 25.

this implies that all possible options, except 24, can be accepted