a man buys 3 cows and 8 goats in 47200. instead , if he would have bought 8 cows and 3 goats , he had to pay 53000 more. cost of one cow

3x+8y=47200 and 8x+3y=100200 

adding them we get          11x+11y=147400 
and subtracting we get       5x– 5y=53000  

 x+y=13400 and x–y=10600 

adding these two final equations we get 2x=24000 

 x=12000