Minimum amount of money that must be spent before three gumballs of the same color are dispense

A vending machine dispenses gumballs in a regular repeating cycle of ten different colors. If a quarter buys 3 gumballs, what is the minimum amount of money that must be spent before three gumballs of the same color are dispense?

Colored beads

there were 198 blue beads in Box A and 219 Pink beads in Box B. some green beads were added to Box A and some yellow beads were added to Box B. for every 3 blue beads in Box A, 13 green once were added to Box A as s result, Box A had 4 times as many beads as Box B. how many yellow beads were added to Box B?

Age Problem: The sum of the ages of the father and his son is 99

Hi Math Wizard, could you please help me to solve this problem with your easiest solution:
The sum of the ages of the father and his son is 99. If the age of the son is added to the inverted age of the father the sum is 72. if the inverted age of the son is subtracted from the age of the father, the difference is 22. what are their ages? Ans: 74 & 25