Question: the distance from city a to city b is 220 miles . while driving from city a to city b , bob drives at a constant speed of 40 miles per hour . alice leaves city a 30 minutes after bob . what is the minimum constant speed in miles per hour that alice must exceed in order to arrive in city b before bob ?
A) 44
B) 48
C) 50
D) 52
E) 54
Correct answer: a
Grade: 6 | Topic: Ratios and proportions | Difficulty: Hard | Standard: 6.RP.A.3b