Pls help, because I need it desperately

1) 13

2) is

3) s/13

Step-by-step explanation:

It’s one adult to 13 students.  It IS proportional.

a=s/13

0.16 or 16%

step-by-step explanation:

lets take a coin for example.

if you toss it twice, it has a 1/4 chance of landing on heads both times because 1/2 * 1/2 is 1/4.

with the cards, the chance of picking dog is 0.4. having two people pick one is like picking a card twice in a row. so 0.4 * 0.4 is 0.16, or 16%