Question 451462
1) Let X = Number of oranges

   1.44/12 = .12 per orange

   4/5X (.6/4) + 1/5X (.25/2) - .12X = 5
   2.4X/20 + .25X/10 -.12X = 5
   .12X + .025X - .12X = 5
   .025X = 5
   X = 200 

3) Ratio 15:6:4 
15+6+4 = 25 
15000/25 = 600 
15*600 = 9000 (5c stamps) 
6*600 = 3600 (6c stamps) 
9000 - 3600 = 5400