Answer: When Lily is 10, Jacob will be 18. When she is 16, he will be 24.
Step-by-step explanation: This is because Jacob is 8 years older than Lily, as seen by subtracting her age from his age (13 - 5 = 8). From there, we just add 8 to Lily's ages from then on. 10 + 8 = 18, and 16 + 8 = 24.