Today's problem solving

WALT: Convert money to time and figure out what time did the parking meter expire. Today in problem solving Kelly and I were solving a question. Since we knew $2=1 hour in a parking meter and 50¢=15m so what we did was $3 was 1h and 30 m we needed to add another 50¢ so we added 15 m and our answer was the parking meter expired at 5pm, because we knew 1h and 45m + 3.15pm= 5pm. What I found challenging was explaining how I got this answer what I found easy was the complete opposite which was writing the question. Next time I will try another strategy to solve this question