Question

ber of ways in which a lawn-tennis mixed double
be made from seven married couples if husband and
wife play in the same set is

Answer 1

Step-by-step explanation:

Thus, from triangle DEC, we can say that cosθ=DECD . From the distance formula, we can say the that the length of DE is 12√3 and CD is √32 . Therefore, the angle between two faces is cos−113 . So, the correct answer is “Option B”.

Answer 2

Answer:

We arrange any 2 men in 7P2 ways and then the wives of the remaining 5 men can be arranged in 5P2 ways. This is because these two men should not be with their respective wives. = 7 !