Question 337490
A group of dogs and ducks have a total of 99 heads and legs among them. There are twice as many ducks as there are dogs. How many are there of each animal?
--------------------
Equations:
Since # of ducks = 2(# of dogs)
Head count: 2d + d
Leg count: 2(2d) + 4d 
-------
Equation:
2d+d+2(2d)+4d = 99
2d+d+4d+4d = 99
11d = 99
d = 9 (# of dogs)
2d = 18 (# of ducks)
=======================
Cheers,
Stan H.