Could anybody explain thses questions?

[pojangchang]

Just don't know WHY? THANK YOU !!!

GMAT DATA SUFFICIENCY OLD QUESTIONS REVIEW
1. What is the average age of the members of the Richmond Chess Club?
(1)The average age, excluding the ages of two absent members, is 24 years, 7 months.
(2)The average age of the two absent member is 18 years, 2 months
A):E [F.14, Q.14] (1)How many total people?
2.
In the figure above, circular region R contains shaded circular region S. The area of R is how many square centimeters greater than the area of
S?
(1)R & S have the same center.
(2)The radius of R is 3 centimeters longer than the radius of S.
A):E [F.14, Q.17]
3.If a certain positive 2-digit number tens¡¦ digit w and units¡¦ digit x, what is the value of w+x?
(1)20w+4x=44 (2)The product of w and x is 2.
A):B [F.14, Q.22] 4. Is the sum of all the terms in a sequence of positive integers an odd integer?
(1)The sequence is composed of consecutive integers.
(2)There are 50 terms in the sequence.
A):C [F.15, Q.23]
5. Is x<1? (1) x>0 (2)1/x<1
A)C [F.15, Q.21]

6. n=24*32*52 and positive integer d is a divisor of n. Is d>¡Ôn¡H
(1)d is divisible by 10. (2) d is divisible by 36
A):C [F.15, Q.23]

7. Exactly 3 deposits have been made in a savings account and the amounts of the deposits are 3 consecutive integer multiples of $7. If the sum of the deposits is between $120 and $170, what is the amount of each of the deposit ?
(1)The amount of one of the deposits is $49. (2)The amount of one of the deposits is $63.
A):B [F15. Q25]