a man has some hens and cows . if the number of heads be 100 and the number of feet equals 240 , then the number of cows will be :
"explanation : let the number of hens be x and the number of cows be y . then , x + y = 100 . . . . ( i ) and 2 x + 4 y = 240 x + 2 y = 120 . . . . ( ii ) solving ( i ) and ( ii ) we get : x = 26 , y = 20 . the required answer = 20 . answer : d"
divide(subtract(multiply(100, const_4), 240), const_2)