2
$\begingroup$

A jar contains some red and some yellow jelly beans. If a child ate 1 red jelly bean, 1/7 of the remaining candies would be red. If instead the child ate 5 yellow jelly beans, 1/6 of the remaining candies would be red. How do I found out the number of jelly beans that are in the jar?

  • 0
    @Andres: Well, 2 linear equations, 2 variables :-)2011-01-18

2 Answers 2

1

HINT $\ $ Put $\rm R = $ #red beans. Then the total #beans $\rm\: =\ 7\ (R-1) + 1\ =\ 6\ R + 5\:.$

4

Use algebra.

Let R be the number of red beans, and Y be the number of yellow beans. Then the second and third sentences can be expressed as equations in R and Y. Solve this pair of equations, and you've got it.

For instance, the second sentence tells us that $\frac{R-1}{R+Y-1}=\frac{1}{7}$.