Solution:
<u>Note that:</u>
<u>Using cross multiplication:</u>
- (3x)/20 = (4x + 2)/28
- => (3x) × 28 = (4x + 2) × 20
<u>Simplifying both sides:</u>
<u>Subtracting 80x both sides:</u>
- 84x = 80x + 40
- => 84x - 80x = 80x + 40 - 80x
<u>Simplify the LHS:</u>
- => 84x - 80x = 40
- => 4x = 40
- => x = 10
In the third step, 10 is the mass of the dog. As such, it should have been substituted to w and not to m.
Blue to orange
6 : 5
24 : x

There are 20 orange M&M's.
Hope this helps. - M