Question 164889
We have 2 unknowns we will call O-oil painting and W-water color.  we need 2 equations to solve these unknows.  the difference between O and W is 35 written as O-W=35.  the age of O five years from now written as O+5 is equal to twice the age of W five years ago written as 2(W-5).  so O+5=2(W-5).  that gives us our 2 equations.  solve for O in the first and you get O=35+W  now substitute this into the second equation and you get  (35+W)+5=2(W-5)  multiply out the right side and you get 35+W+5=2W-10  solve for W which equals 50. Now we know that O=35+W(50)  so O=85  

answer Oil painting 0=85
       Water color  W=50