Explain #2 for me !
the question deals with proportions.

We claim that the ratio of the areas is (3/2)^3=27/8, not just for these lengths, but also for every possible set of side-lengths x, y, and z.

To find the volume of the area of the original suitcase, multiply together x, y, and z to get xyz.  The modified suitcase will have all these dimensions multiplied by 1 1/2, or 3/2, for a result of 3x/2*3y/x*3z/2=27xyz/8.  The ratio is (27xyz/8)/(xyz)=27/8, as desired.

Note that we made no assumptions about the value of x, y, and z throughout the whole solution!  Therefore, we can plug ANY side-lengths, including the problem's set (28, 16, 8) into this problem to achieve the same ratio.

10 will be the number of adult tickets and 11 will be the number of children tickets. i hope i could ! good luck : )