Answer:
There are 26 birds and 17 beasts.
Birds and beasts have one head each. So totally there are 43 birds & beasts.
Let number of birds = x
number of beasts = (43-x)
Birds have 2 feet and beasts have 4 feet.
Total feet = 2 * no of birds + 4 * no of beasts
= 2 * x + 4 * (43 -x)
= 172 - 2*x (on simplification)
= 120 (given)
172 - 2*x = 120
2*x = 172 - 120 = 52
x = 52/2 = 26
number of birds = x = 26
number of beasts = 43 -x = 43 -26 = 17
(check: 26 + 17 = 43 ; 26*2 + 17*4 = 52 + 68 = 120)
