Answer :

no, 0.75 is 3/4 and 15 is 60/4 therefor add them together to get 63/4, which can't be cancelled down.  Therefor 15.75 is 63/4 as a fraction. It is not 15/7500 15 is smaller than 7500 therefor there would be no whole numbers. Remember a fraction is one thing dividing by another. 
apologiabiology
to convert decimals to fractions is easy
.75=75/100 or 3/4

so 15.75=63/4

also since 15/7500 is less than one, it cannot be equivilent to 15.75