Let b represent blue marbles g represent green marbles Then, We know that there are three times as many blues as green ones, so b=3g Next, the bag contains 280 marbles total, so: b+g=280 marbles Substitute b=3g into this equation, to get 3g+g=280 marbles 4g=280 marbles Divided 4 to each side 4g/4=280/4 g=70 marbles b=3r b=3(70) b=210 marbles Check: b=3r 210=3(70) 210=210 b+g=280 210+70=280 280=280. As a result, there area 210 blue marbles. Hope it help!
