Hey there,

Yes,they are helpful for the online test practice preparation of JEE Main, JEE Advanced, AIPMT, AIIMS, BITSAT, CBSE Class VI to X, NTSE and Various International, National Olympiads but you must have to read NCERT books for basics.

Hi,

yes they are much Helpful for the preparation but instead of this you should take help of ncert book .You can also solve the previous year paper. 

Thanks