How many different signals can be made by hoisting two yellow flags, three green flags, and five red flags on a ship's mast at the same time? i tried doing (11 c 2)(11 c 3)(11 c 5) and that doesn't work.

Given:
2 yellow flags
3 green flags
5 red flags

for a total of 10 flags.

It is a permutation of 10 objects, not all distinct.

The number of permutation is: 
     10!            3,528,800
=    = 2,520
2! * 3! * 5!        1,440

There are 2,520 different signals that can be made using the given flags.

28 pounds of clothing

Step-by-step explanation:

Here the given table,

Weight of clothing  :       22             28              34             36            

Cups of dye             :        5.5            6.5             8.5              9

Since, the ratio of 22 pounds of clothing and 5.5 cups of dye

=

The ratio of 28 pounds of clothing and 6.5 cups of dye

=

The ratio of 34 pounds of clothing and 8.5 cups of dye

=

The ratio of 36 pounds of clothing and 9 cups of dye

=

Thus, by the above explanation,  we can say that the ratio of the 28 pounds of the cloth and the 6.5 cups is different from other ratios.