The correct question is;
Last night, Roberto spent 90 minutes doing homework, 2/3 hour reading, and 540 seconds making his lunch for the next day. How many more minutes did Roberto spend doing homework than he did reading and making his lunch? 81 minutes 50 minutes 49 minutes 41 minutes
Answer:
41 minutes
Explanation:
We are given;
Time spent on homework = 90 minutes
Time spent reading = 2/3 hours = 2/3 × 60 minutes = 40 minutes
Time spent making lunch = 540 seconds = 540/60 minutes = 9 minutes
We want to find how many more minutes Roberto spent doing homework than he did reading and making his lunch.
Thus;
Time spent on reading and making lunch = 40 + 9 = 49 minutes
Hence, the word "how many more" means we will subtract 49 from 90.
So, "how many more minutes" = 90 - 49 = 41 minutes