Andrea has 3 hours to spend training for an upcoming race. She completes her training by running full speed the distance of the race and walking back the same distance to cool down. If she runs at a speed of 7mph and walks back at a speed of 3mph , how long should she plan to spend walking back?

The equation m = 19.32v can be used to find the mass m in grams of a pure gold coin with volume v in cubic centimeters. carl has a coin with a mass of 37.8 grams. the coun's volume is 2.1 cubic centimeters. could the coin be pure gold? explain your reasoning. whoever answers this correctly gets marked brainliest! this is also worth a decent amount of points than normal questions!