Question 386257
I feel the easiest way to solve proportions is to cross multiply in an X shape.

1.5/2       =       7.5/w                                                
 
Multiply 1.5 and w, then set that equal to 2 and 7.5 multiplied together.                                                   
1.5(w)=2(7.5)
                                                                
1.5w=15   Then divide by 1.5 to solve for w
                
 w=10

You can solve any proportions like this and it makes it pretty easy. Hope that helped!