math exams

Q1. If $3x-21y=15$, then $7y-x$ is $-5$ $5 $ $3 $ $7 $ Cannot be determined Q2. 

How many different 7-place license plates are possible if the first 2 places are for letters and the other 5 for numbers? Ans : 67 600 0...

What is the probability that the arrangement has both consecutive W's and consecutive Y's in WYSIWYG? Ans. 0.0952

A group of students consists of 4 boys and 4 girls. How many ways are there to select 2 students of same sex from the group. Ans. 12 ...

In how many ways may fifty-two cards be divided amongst tour players, so that each may have thirteen ? Ans. $\frac{52!}{(13!)^4}$