Answer:
It would take 4 hours for both candles to be the same height
Step-by-step explanation:
Total time (t) for red candle to be same height (h) can be expressed as;
Final height after time t=Initial height-rate per hour
where;
Final height after time=h
Initial height=8 inches
Rate per hour=rate×time=(7/10)×t=0.7t
Substituting;
h=8-0.7t
Total time (t) for blue candle to be same height (h1) can be expressed as;
Final height after time t=Initial height-rate per hour
where;
Final height after time=h1
Initial height=6 inches
Rate per hour=rate×time=(1/5)×t=0.2t
Substituting;
h1=6-0.2t
Since h=h1
8-0.7t=6-0.2t
8-6=0.7t-0.2t
0.5t=2
t=2/0.5
t=4 hours
It would take 4 hours for both candles to be the same height
