Step-by-step reasoning process: Billy's age is 30 / 3 = 10 years old. The sum of the ages of Billy and Lucas is 30 / 2 = 15. So, Lucas is 15 - 10 = 5 years old now. Therefore, Lucas will be 5 + 3 = 8 years old three years from now.
The question and answer:
Question and answer: The age of Gladys is equal to twice the sum of the ages of Billy and Lucas. Billy is 3 times younger than Gladys who is 30 years old now. How old will Lucas be three years from now?
The answer is 8

Step-by-step reasoning process: Eric has a total of 12 + 6 = 18 white and blue marbles. Thus, he has 20 - 18 = 2 green marbles.
The question and answer:
Question and answer: Eric has 20 marbles. He has 12 white marbles, 6 blue marbles, and the rest are green marbles. How many green marbles does Eric have?
The answer is 2

Step-by-step reasoning process: Ed found 7 shells + 2 shells + 4 shells = 13 shells at the beach. Jacob found 13 shells + 2 shells = 15 shells at the beach. In total Ed and Jacob have 2 shells + 13 shells + 15 shells = 30 shells.
The question and answer:
Question and answer:
Ed and Jacob already had 2 shells in their shell collection. Then they went to the beach to collect even more. Ed found 7 limpet shells, 2 oyster shells, and 4 conch shells. Jacob found 2 more shells than Ed did. How many shells do the pair have altogether?
The answer is 30