Hitomi has a total of 30 red and blue bowling balls ate her bowling alley. Each red ball weighs 8 lb. Each blue ball weighs 9 lb. If the total mass of the blue balls is 49 lb. heavier than the total mass of the red balls, how many red balls does she have?

2 answers

http://www.jiskha.com/display.cgi?id=1299027587
I need help