math
posted by stacey .
total of 17 heads and 42 feet with 3 times more ducks as pigs so how many duck do you have

there are 4 pigs and 13 ducks

well, the only way there can be 17 heads and 42 feet and 3 times more ducks, would be: 4 pigs (4 heads and 4 feet for each
4x4= 16 feet
13 ducks ( 13 heads and 2 feet each
13x2 =26 feet
Heads = 4+13=17 for 4 pigs
feet =16+26=42 for 13 ducks
4(Pigs) X 3 = 12
so there are 3 times more ducks 
number of pigs  x
number of ducks  3x
for heads: x + 3x = 17
4x = 17
x = 17/4 , which is not a whole number, so the question is bogus
There is no answer, the way it is worded.
However, if we skip the fact that there are 3 times as many ducks as pigs, we can solve it
number of pigs  x
number of ducks  y
for heads: x + y = 13
for feet:
4x + 2y = 42
2x + y = 21
2x + y = 21
x + y = 17
subtract them:
x = 4
then y = 13
that is the answer that Surya Teja had given, but it would not have met the condition that there 3 times as many ducks as pigs, since 3x4 ≠ 17