how to solve these problems

[eumreem]

Is the hunderdths of the decimal D greater than 5 ?
1.The tenths digit of 10D is 7 ?
2.The thousandths digit of D/10 is 7


A grocer buys apples for 63$ per pound.if 10%of the apples go bad and he still wants to make a 20%profit over his purchase price ,what should be the sales price ?
A) 66
B) 70
C) 75
D) 77
E) 84

these questions from the gmat avengers guide

[RonPurewal]

hi,
please follow the forum rules:

• separate thread for each question

• title of the thread = first few words of the problem

thanks.

[RonPurewal]

also-- when you re-post these problems, you should give some specifics of what you've already tried.
what do you understand?
what don't you understand?
what have you already tried?
if there's an answer key, what does it say, and what about that explanation doesn't make sense to you?

thanks.