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Answer:
- older sister: 4 mph
- younger sister: 2 mph
Step-by-step explanation:
Since the sisters are walking in opposite directions, the amount of distance between them increases at a rate equal to their combined walking speeds. That rate is ...
speed = distance/time
speed = (30 mi)/(5 h) = 6 mi/h
If y represents the speed of the younger sister, their combined speeds are ...
y +2y = 6
3y = 6
y = 6/3 = 2 . . . . . . . younger sister's speed
2y = 2(2) = 4 . . . . . older sister's speed
The older sister's speed is 4 miles per hour; the younger's speed is 2 miles per hour.
