Information you will need to answer the question:
You would have to convert 1.5 hours into minutes which is 90 minutes.
You would then divide 90 minutes by 10 minutes because 5.2°C is dropping every 10 minutes,
Multiply how much the temperature drops by 9 to find the total of how much it drops all together.
You then subtract your original temperature of 19°C by 46.8 to get your answer of (-27.8).
This is the grade 9 way.
Always write a sentence answer after a word problem.