Answer :

consecutive means right after each other like 1, 2, 3, 4...so if the first sister is x old, then sister 2 is (x+1) old and sister 3 is (x+2) old.  So make an equation that says x+(x+1)+(x+2)=45.  Simplify and solve for x (get x alone.)
the first sister is 14 the second sister is 15 and the third sister is 16

45-3=42

42 divided by 3 equals 14 

14+1=15+1=16

14+15+16=45