Your parents gave you $50 to take your younger brother and sister to the movies.

$24.25

Explanation:

Given:

Amount given by parents = $50

So, $50 can be considered as income.

Following are the expenses:

Cost of ticket for adult = $7.25

Cost of ticket for children = $4.25

Cost of ticket of 2 siblings = 4.25 × 2 =  $8.5

Cost of Soda and Popcorn = $10

Total expenses = 7.25 + 8.5 + 10 = $25.75

Amount left after expenses = Income - expenses

                                              = $50 - 25.75

                                              = $24.25