What is the most effective way of using OG11 PS and DS. What happens is, If I can't solve the problem, I read the answer and try to solve the question again. But the second time around I remember that problem and am able to solve it again. But it doesn't indicate that I will get it right if it is changed slighlty. I am confused. Are 500 PS and DS question on wiki worth solving to get more practice. What is the source of those problems.
Any tips will be helpful.
thanks,
RP
Any tips will be helpful.
thanks,
RP

















