求教两道数学题目

cub103

37.For every integer k from 1 to 10, inclusive, the kth term of a certain sequence is given by   .  If T is the sum of the first 10 terms in the sequence, then T is

(A) greater than 2
(B) between 1 and 2
(C) between 1/2 and 1
(D) between 1/4 and 1/2
(E) between 1/4

38.Three grades of milk are 1 percent, 2 percent, and 3 percent fat by volume.  If x gallons of the 1 percent grade, y gallons of the 2 percent grade, and z gallons of the 3 percent grade are mixed to give x + y + z gallons of a 1.5 percent grade, what is x in terms of y and z ?

(A) y + 3z
(B) (y + z) /4
(C) 2y + 3z
(D) 3y + z
(E) 3y + 4.5z