Answer:
20 km/h
Step-by-step explanation:
the total time is 0.5 hours as the cyclist travels for 30 minutes
the formula for speed is distance travelled divided by time taken which gives us 20 km/hr
First you need to get 3% of 7 so
7x0.03= 0.21
then you need to add that 3% onto 7
7+0.21=7.21
therefore the door frame is now 7.21 feet high
