There is no shortcut to solve any problems if you understand the problem properly and apply the concepts you learnt then problem is very easy to solve don't go for tricks and shortcuts their temporar and  and can provide you a temporary success may be in Engineering entrance exam for medical entrance exam but what is more important is concept not the tricks or not your ability to solve the problem if you are able to solve your problems but understanding the concept then they will help you to solve many more problem but if you try to use some shortcuts then then maybe applied to few problems but not for all and trust me the people who prepare entrance exam papers they know everything and they also take care that people who are aware of the concept should be able to solve the problem not the ones who can apply short cut or tricks.