【正确答案】
C
【答案解析】Let m and w, respectively, be the number of metal frames and wooden frames that Tami purchased, and let M and W, respectively, be their individual prices in dollars. We are given that mM+ wW=144. What is the value of mM?(1) Given that M= 1.6W= 8W/5, or W= 5W/8, we have mM+ w (5W/8) =144. Although it might seem there is not enough information to determine the value of mM, keep in mind that we are only seeking the value of the product mM, and not the individual values of m and M. Also, there are several implicit constraints involved, such as each of M and W must be a positive number less than 144 and each of m and w must be a positive integer. To see that more than one value of mM is possible, it will be convenient to specify a particular value for w, for example,w= 16. Then mM+w(5W/8)=144becomes mM= 144 - 10M, and non-sufficiency is now straightforward. If w = 16 and M= 4, then mM= 104. However, if w = 16 and M= 8, then mM= 64; NOT sufficient.(2) Given that w = 2m, we have mM+ (2m)W= 144, or mM= 144 - 2mW. If m = 10 and W= 4, then mM= 64. However, if m = 10 and W= 5, then mM= 44; NOT sufficient.Given (1) and (2), we have W= 5M/8 and w = 2m.Therefore, mM+ wW= 144 becomesmM+{2m)(5M/8)=144,or(1+5/4)mM=144,and hence the value of mM can be determined.The correct answer is C;both statements together are sufficient.