Along a street that is currently without trees, seven trees are to be planted in the pattern

　　1 3 5 7

　　2 4 6

　　Where each number designates the position of a tree. No more than two kinds of trees can be planted. If maples are used, no maple can be planted adjacent to or immediately diagonally opposite another maple. Two trees are adjacent to each other if the numbers of their positions differ by two, and immediately diagonally opposite f their numbers differ by one. The following trees, of three kinds, are available for planting:

　　Three red oaks

　　Four maples

　　Four sycamores

　　19.Which of the following can be the trees planted along the side of the street that has four trees, in order of their positions beginning with position 1?

　　(A)Maple, sycamore, maple, sycamore

　　(B)Maple, sycamore, red oak, maple

　　(C)Red oak, maple, maple, red oak

　　(D)Sycamore, sycamore, maple, maple

　　(E)Sycamore, sycamore, red oak, red oak

　　20.If red oaks are used, then which of the following must be true?

　　(A)The other trees used are all maples.

　　(B)The other trees used are all sycamores.

　　(C)The red oaks are in positions 1, 2, and 3.

　　(D)The red oaks are in positions 3, 4, and 5.

　　(E)The red oaks are in positions 4, 5, and 6.

　　21.Among the trees left over after the planting is done there must be

　　(A)at least one maple

　　(B)at least one red oak

　　(C)at least one sycamore

　　(D)at most one maple

　　(E)at most one red oak

　　22.If maples are planted, the side of the street that has four trees must have

　　(A)red oaks in positions 1 and 7

　　(B)red oaks in positions 3 and 5

　　(C)sycamores in positions 1 and 3

　　(D)sycamores in positions 1 and 7

　　(E)sycamores in positions 3 and 5

　　23.A list of the fifteen operas most frequently performed in recent times includes no works by the nineteenth- century German composer Richard Wagner. lhough music producers tend to produce what audiences want, relative infrequency of performance probably does not indicate lack of popularity in Wagner's case, since Wagner's operas are notoriously expensive to perform on stage.

　　Which of the following, if true, most strongly supports the conclusion of the argument above?

　　(A)The list of most frequently performed operas does not include operas produced by small amateur groups.

　　(B)Some opera companies are backed by patrons who are willing to commit large sums of money in order to enjoy lavish productions.

　　(C)All of the fifteen most frequently performed operas of recent times are works that have been popular for at least 75 years.

　　(D)More recordings have been produced recently of the works of Wagner than of the works of anyother composer of opera.

　　(E)Operatic works of all kinds have been increasing in popularity in recent years.

　　24.The bodies of dwarf individuals of mammalian species are generally smaller in relation to those of nondwarf individuals than are the teeth of the dwarf individuals in relation to those of the nondwarf indi-viduals. Fragmentary skeletal remains of an adultdwarf woolly mammoth were recently found. The teeth are three-fourths the size of the teeth of an average adult nondwarf woolly mammoth.

　　The statements above, if true, most strongly support which of the following?

　　(A)The body of the dwarf woolly mammoth was less than three-fourths the size of the body of an average adult nondwarf woolly mammoth.

　　(B)None of the teeth of the dwarf woolly mammoth that were recently discovered was as large as any of the teeth of nondwarf woolly mammoths that have been discovered.

　　(C)The teeth of most adult dwarf individuals of mammalian species are three- fourths the size of the teeth of the adult nondwarf individuals of the same species.

　　(D)Dwarf woolly mammoths had the same number of teeth as did nondwarf woolly mammoths.

　　(E)Dwarf individuals of most mammalian species are generally no more than three-fourths the size of the adult nondwarf individuals of those speies.

　　25.Excluding purchases by businesses, the average amount spent on a factory-new car has risen 30 per-cent in the last five years. In the average household budget, the proportion spent on car purchases has remained unchanged in that period. Therefore theaverage household budget must have increased by 30 percent over the last five years.Which of the following is an assumption on which the argument relies?

　　(A)The average number of factory-new cars pur-chased per household has remained unchanged over the last five years.

　　(B)The average amount spent per car by businesses buying factory-new cars has risen 30 percent in the last five years.

　　(C)The proportion of the average household budget spent on all car-related expenses has remained unchanged over the last five years.

　　(D)The proportion of the average household budget spent on food and housing has remained unchanged over the last five years.

　　(E)The total amount spent nationwide on factory-new cars has increased by 30 percent over the last five years.