Evaluate the given expression. do not use a calculator
(5/4)^(-4)

When something has a negative power you must move it to the denominator to give it a positive power therefore this would then turn into 1/[(5/4)^4]  to simplify this (5/4)^4 would be (25/16)(25/16) then finally (625/256) so it would then look like this 1/(625/256) in order to not have a fraction in the denominator you would multiply; 1 x (256/625) which is 256/625.

(5/4)^(-4) = 1/(5/4)^4
1/(5/4)(5/4)(5/4)(5/4)
1/(625/256)
1/(2 113/256)
 256/625

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