SOLUTION: There are 7 red marbles for every 3 blue marbles in a collection. the collection has 420 more red marbles than blue marbles. How many marbles are there in the collection. show the

Algebra ->  Probability-and-statistics -> SOLUTION: There are 7 red marbles for every 3 blue marbles in a collection. the collection has 420 more red marbles than blue marbles. How many marbles are there in the collection. show the       Log On


   

Question 418743: There are 7 red marbles for every 3 blue marbles in a collection. the collection has 420 more red marbles than blue marbles. How many marbles are there in the collection. show the work


Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

420 more red marbles than blue marbles

Let x and (x +420)represent the amount of blue and red respectively

Question Sets Up the Proportion

  7%2F3+=+%28x%2B420%29+%2Fx    |Cross Multiplying to solve

      7x = 3(x+420) 

      4x = 1260

       x = 315, blue marbles and 735 red marbles  (315+420)



CHECKING our Answer***

 735/315 = 7/3