Question 1099270
To answer this, we must assume that Betty and Carl both leave home at the same time, and arrive to work at the same time. Let m and n be the distances between apartments to car park, and car park to office, respectively. Then:
m km/60(km/h)+n km/4(km/h)=m km/40(km/h)+n km/12(km/h)
2m km + 30n km=3m km+10n km
m km=20n km
m=20n
Let n=2. Then m=40.
40 km/60 (km/h)=2/3 hr=40 min
2 km/4 (km/h)=1/2 hr=30 min
40+30=70
40 km/40 (km/h)=1 hr=60 min
2 km/12 (km/h)=1/6 hr=10 min
60+10=70 min
If they both leave at 6 a.m., they both get to work at 7:10 a.m.
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