Basically, the fractions are 2/5 vs. 3/8. As always, in order to compare fractions, you must first have a common denominator. The easiest way to achieve that is by multiplying the two denominators by each other. 5*8=40. You must also multiply the numerators by the same thing you multiplied the denominators by, so 3*5=15, and 2*8=16. The new fractions are 16/40 vs. 15/40. Therefore, Vet A has seen more dogs.