2,500+2000a=47,900-800a
2,500+2000a=47,900-800a-2,500 -2,5002000a=45,400-800a+800a +800a2800a=45,400/2800 /2800a = 16.21
2,500+2000a=47,900-800a=> 2000a + 800a = 47900 - 2500=> 2800 a = 45400=> a = 45400 / 2800=> a = 227/14 Hope it helps!!!