Find the time when they meet

Question

at 9:30am Andrew left Exeter for Portsmouth, cycling at 12 mi/h. At 10:00am Stacy left Portsmouth for Exeter, cycling at 16mi/h. The distance between Exeter and Portsmouth is 20 mi.

Answer 1

time for Stacy is t
time for Andrew is t + 0.5
d = r · t
12(t + 0.5) + 16t = 20

Can you solve for t?