A duck is in front of two ducks; a duck is behind two ducks; and one duck is in the middle. What is the minimum number of ducks that can fulfill this condition?

Seven boxes P, Q, R, S, T, U and V are kept one over the other, but not necessarily in the same order. Q is kept immediately above P. S is kept immediately above V. Only R is kept above U. Only two boxes are kept above Q. S is not kept at the third position from the bottom. How many boxes are kept between R and T?

Read the data given below and answer the following question: Six teachers namely, Abhijit, Binod, Chandan, Dinesh, Emraan and Farhan have been scheduled to take Mathematics classes from Monday to Saturday for only one week. Each teacher takes classes on a different day. The number of classes they are allowed to take are 2, 3, 4, 5, 6 and 7, but not necessarily in the same order. Binod takes 5 classes but he is scheduled neither on Monday nor on Saturday. Abhijit takes classes on Wednesday but not 3 classes. The teacher who takes 7 classes is scheduled on Tuesday but he is neither Chandan nor Dinesh. The teachers who take 6 and 2 classes are scheduled on consecutive days. The one who takes classes on Saturday doesn't take 6 classes. Chandan is scheduled to take classes on the day immediately following Farhan's classes. Emraan prefers to teach on Tuesday or Friday. What is the total number of classes taken by Dinesh and Emraan together?