I'm having trouble doing the following problem in

OG 12.

89. Is the number of members of Club X greater than the

number of members of Club Y ?

(1) Of the members of Club X, 20 percent are also

members of Club Y.

(2) Of the members of Club Y, 30 percent are also

members of Club X.

121. In the xy-plane, region R consists of all the points (x,y)

such that 2x + 3y ≤ 6. Is the point (r,s) in region R ?

(1) 3r + 2s = 6

(2) r ≤ 3 and s ≤ 2

161. Beginning in January of last year, Carl made deposits

of $120 into his account on the 15th of each month

for several consecutive months and then made

withdrawals of $50 from the account on the 15th of

each of the remaining months of last year. There were

no other transactions in the account last year. If the

closing balance of Carl’s account for May of last year

was $2,600, what was the range of the monthly

closing balances of Carl’s account last year?

(1) Last year the closing balance of Carl’s account

for April was less than $2,625.

(2) Last year the closing balance of Carl’s account

for June was less than $2,675.

Will appreciate if anyone explains them better than the book.