(t+7/20) - 8/15 = 11/15

Solve for t:

1. (t + 7/20) - 8/15 = 11/15
2. Combine constants: 7/20 - 8/15 = -11/60, so t - 11/60 = 11/15
3. Add 11/60 to both sides: t = 11/15 + 11/60
4. Put over 60: 11/15 = 44/60, so t = 44/60 + 11/60 = 55/60 = 11/12

Answer: t = 11/12

Quick check: t + 7/20 = 11/12 + 7/20 = 55/60 + 21/60 = 76/60 = 19/15; subtract 8/15 gives 11/15. Correct.