if a guy joins any reputated institute for iit by taking drop..

do they teach each concept again in detaliled manner??

Dear Amit,
as per to me
they do go in detail,but they hurry a bit in completing them,
so its natural that the student feels a little tough to go accordingly.
the student needs to be a good listener and hardworker.
giving drop means full day working in all 365 days,
then only giving a drop makes "SENSE".
Regards

they just revise your weak areas and help you solve as many problems as possible