感觉GMAT数学不简单啊 问三道PREP！

lllmmm

第一道： DS题   6 countries in a certain region sent a total of 75 representatives to an international congress, and no 2
countries sent the same number fo representatives. Of the 6 countries, if Country A sent the second greatest number of
representatives, did Country A send at least 10 representatives?
(1) one of the 6 countries sent 41 representatives to the congress
(2) Country A sent fewer than 12 representatives to the congress

第二道：（看不懂）The cost of a square slab is propotional to its thickness and also propotional to the square of its length. What is the
cost of a square slab taht is 3 meters long and 0.1 meter thick?
(1)The cost of a square slab that is 2 meters long and 0.2 meter thick is $160 more than the cost of a square slab that is 0.1
meter thick.
(2)The cost of a square slab that is 3 meters long and 0.1 meter thick is $200 more than the cost of a square slab  that is 2
meters long and 0.1 meter thick

第三道：If each term in the sum a1+..+an is either 7 or 77 and the sum equals 350, which of the following could be equal
to n?  答案：40