John weights twice as much as Marcia, so John cannot weight the least. Marcia's weight is less than Bob's weight, so Bob's weight is not the least. Dave's weight is 1/2 of Lee's weight. So Lee can't weight the least. The only possible answers are Marcia or Dave. Let J.M.B.D. and L stand for the weights of John, Marcia, Bob, Dave and Lee respectively. Then D = .5L = .5(1.9)J. So D = .95J. Since J = 2M, we know M = .5J. Therefore Marcia weights the least.