STEAL PTS I REALLY NEED TO GET A GOOD GRADE ON THIS AND PLS READ THE ANSWER CHOICES BEFORE YOU HELP ME I ALSO NEED ALL THREE ANSWERS IN ORDER TO PASS

Ill mark the brainliest if you me with the these three questions 7,8,9

Olga bought a new skirt that cost $20. sales tax is 5%. how much did olga pay, including sales tax? 7.

At a local museum, the total price for one adult and one child is $11. mrs. smith paid for herself and her three children. she spent $19. record the system of equations to be solved and then find the price of an adult and child ticket using either elimination or substitution.