Gmat Problem solving

"delivery of unit" and "problem solving"
This unit runs over 12 weeks and will be covered by interactive lectures,demonstrations and laboratory exercises.All fundamentals of this course are contained in the programmed text.Students will be encouraged to bring in problems from other areas and use the tutorial times as workshops for solving those problems.
2-hour lecture Friday 8:30
1-hour tutorial Friday 10:30
1-hour problem solving Friday 11:30
what are the two phrases meaning?

GMAT OG12 problem solving的几道题
P274 14题这句话看太不懂：Car X drove onto the bridge exactly 3 seconds after Car Y drove onto the bridge and drove off the bridge exactly 2 seconds after Y drove off the bridge.
P274 18题what is the maximum number of rectangular blocks,each with dimensions 12 centimeters by 6 centimeters by 4 centimeters,that will fit inside rectangular Box
(1)when Box X is filled with the blocks and rests on a certain side,there are 25 blocks in the bottom layer.说实话书后面这个(1)的答案我看得不太懂,你们能不能帮我看看啊!
P274 23题 the profit from the sale of a certain applicance increases,though not proportionally,with the number of units sold.did the profit exceed $4 million on sales of 380,000 units?
(1)The profit exceed $2 million on sales of 200,000 units.
(2)The profit exceed $5 million on sales of 350,000 units.
P279第70题 Mary persuaded n friends to donate $500 each to her election campaign,and then each of these n friends persuaded n more people to donate $500 each to Mary's campagin.If on one donated more than once and if there were no other donations,what was the value of
答案(2)中 500（n的平方+n）=120000
这个n的平方怎么算的,