M, N, O, P, Y and Z live on six different floors of the same building. The lowermost floor in the building is numbered 1, the floor above it, number 2 and so on till the topmost floor is numbered 6. Only two people lives between N and Z. Only M lives above P. Y lives on an even numbered floor. N lives on the lowermost floor. How many people live between O and M?
What will come in the place of the question mark (?) in the following equation, if '+' and '−' are interchanged and '×' and '÷' are interchanged?
51 ÷ 12 + 162 × 3 − 104 =?