A pair of $72 sneakers is marked with a sign $20 OFF or 20% OFF: The $20 of final price is

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?

Someone this asap for a group of students attends a basketball game. * the group buys x hot dogs at the concession stand for $2 each. * the group buys y drinks at the concession stand for $3 each. the group buys 29 items at the concession stand for a total of $70. how many hot dogs did the group buy?

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?