Question

A very old vending machine accepts only nickels (n) and dimes (d). Candy costs up to $0.50, but sometimes the machine will dispense candy without any coins being inserted into the machine. Which inequality shows all of the ways to obtain a candy bar from the machine

Answer 1

Candy costs up to $0.50. that means it can cost only till 0.50 no higher than that and 0.50 itself so. 50 cents is 1/2 a dollar.

Now a nickel equals 5 cents. 5 cents is 1/20th of a dollar.
Remember, one dollar = 100 cents

A dime equals 10 cents. 10 cents is 1/10th of a dollar

We get the inequality
as your final answer.