.
I will help you with part (2), ONLY.
-----------------------------------------
Actually, according to the problem's context, you select 2 defective calculators from 5 defective,
and then add to these 2 -- two other good calculators, selecting them from 12-5 = 7 good calculators.
The first selection can be made in = = 10 ways.
The second selection can be made in = = 21 ways.
Hence, the whole selection can be made in 10*21 = 210 ways. ANSWER
Solved.
---------------
Please NEVER load more than one problem per post.
B E C A U S E
a) it is against your own interests
and
b) it is PROHIBITED by the rules of this forum.