Answer:
the answer is $120
Step-by-step explanation:
60+60 is 120
It would be the third one 7n=10-3n
Train A:
Distance (s) = 420 miles
Time (t) = 3 hours
Speed (v) = distance ÷ time = 420 ÷ 3 = 140 miles/hour
Train B:
Distance (s) = 420 miles
Time (t) = 2.25 hours
Speed (v) = distance ÷ time = 420 ÷ 2.25 = 186.7 miles/hour