Actually you should try to solve the examples given in RS Aggarwal's book. After that you will not face difficulty in solving exercise problems, well most of them.
There are many publications which offer guide to them,you can find them at any local book store. I think ND books which give keys for NCERT books give for RS too.
However i strongly suggest you avoid guides, rather go for RD Sharma. Its just another books but its examples match with RS's exercises questions very much.