Question 990125

The ratio of red jelly beans to yellow jelly beans in a dish is 3:4. If Greg eats 3 red jelly beans and 6 yellow ones,the ratio is 4:5. How many yellow jelly brans were orginally in the dish?
<pre>Let multiplicative factor be x
Then he had: 3x red, and 4x yellow, originally
We then get: {{{(3x - 3)/(4x - 6) = 4/5}}}
4(4x - 6) = 5(3x - 3) ------- Cross-multiplying
 16x - 24 = 15x - 15
16x - 15x = - 15 + 24
x, or multiplicative factor = 9

Original number of yellow: 4(9), or {{{highlight_green(36)}}}