Is a biased sample is valid always true or never true

Pj is decorating pupcakes for rocky's birthday party. her color scheme is black, purple, and green. she will use this spinner to determine the color of sprinkles on each pupcake. which model shows the probability of randomly landing on each color?

Arestaurant gives out a scratch-off card to every customer. the probability that a customer will win a prize from a scratch-off card is 25%. design and conduct a simulation using random numbers to find the experimental probability that a customer will need more than 3 cards in order to win a prize. justify the model for your simulation, and conduct at least 10 trials.

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.