Answer:
y < - 12
Step-by-step explanation:
y + 15 < 3 ( subtract 15 from both sides )
y < - 12
You have to calculate how many combinations of 6 people can be chosen from 11. The formula for this is:
n! / [r! * (n-r)!]
combinations = 11! / [6! * 5!] =
11 * 10 * 9 * 8 * 7 / 5 * 4 * 3 * 2 *1 =
11 * 3 * 2 * 7 =
462 Combinations
Source:
http://www.1728.org/combinat.htm
Since it decreased by 5 do 5 divided by 30 and you get the answer to be 16%

Hope you could get an idea from here.
Doubt clarification - use comment section.