Part A = She incorrectly add 1 (4/4) with 3/4, so instead of getting 7/4 she got 8/4.
Part B=She needs 28/4 (7) cups for 4 batches because 4/1x7/4=28/4.
5x^2y is the greatest common factor
If Dan is 8x years old next year then he must be 8x-1 years old this year
With the same logic, five years ago from this year, he must be 8x-1-5=8x-6
The answer should be 8x-6
Let:
x = cost of senior citizen ticket
y = cost of student ticket
4x + 5y = 102
7x + 5y = 126
4x + 5y = 102
4x = 102 - 5y
x = (102 - 5y)/4
x = 102/4 - 5y/4
7x + 5y = 126
7(102/4 - 5y/4) + 5y = 126
(714/4 - 35y/4) + 5y = 126
-35y/4 + 5y = 126 - 714/4
note:
-35y/4 = -8.75y
714/4 = 178.5
-8.75y + 5y = 126 - 178.5
-3.75y = -52.5
y = -52.5/-3.75
y = 14
x = 102/4 - 5y/4
x = 102/4 - 5(14)/4
x = 8
x = cost of senior citizen ticket = $8/ea
y = cost of student ticket = $14/ea
