kcjenkins Posted August 6, 2007 Report Share Posted August 6, 2007 At a recent visit to the reptile house at the local zoo, I counted a total of 27 heads and 70 feet. I was counting snakes, lizards and people and I know that there were exactly twice as many lizards as people. How many snakes did I count? Quote Link to comment Share on other sites More sharing options...
jklcpa Posted August 6, 2007 Report Share Posted August 6, 2007 6 snakes, 14 lizards, 7 humans Quote Link to comment Share on other sites More sharing options...
kcjenkins Posted August 7, 2007 Author Report Share Posted August 7, 2007 Very good. Did you calculate it, or google it? Quote Link to comment Share on other sites More sharing options...
jklcpa Posted August 7, 2007 Report Share Posted August 7, 2007 calculated, sort of: 1 human for every 2 lizards. Meaning that 1 human & 2 lizards would have a total of 10 legs. 80% of legs would belong to the lizards, since snakes have no legs. 70 legs * 80% = 56 legs for the lizards / 4 legs per lizard = 14 lizards. 14 lizards, so 1/2 # of humans = 7 & the remaining # must be the snakes at 6. It proved out with the total # of heads at 27. Surely, someone will post the algebraic formula that is easier than my way. :) Quote Link to comment Share on other sites More sharing options...
jainen Posted August 7, 2007 Report Share Posted August 7, 2007 >>4 legs per lizard<< Not necessarily. Lizards are close relatives of snakes, and they don't all have legs. The Glass Snake, for example, is a common legless lizard (it has movable eyelids so we know it isn't a true snake). It's just the sort of oddity that reptile house managers like to display to generate interest. Quote Link to comment Share on other sites More sharing options...
kcjenkins Posted August 7, 2007 Author Report Share Posted August 7, 2007 I did it this way: x=people and people have 2 legs and lizards have four legs and there are two lizards, thus 8 legs for every two people legs. 2x+8x=70 10x=70 x=7 Once you have the number of people, and lizards, the snakes are whatever it takes to make the difference in heads. 7H+14H -Snake Heads =27 Snake heads =27-21 Quote Link to comment Share on other sites More sharing options...
Pacun Posted August 7, 2007 Report Share Posted August 7, 2007 I got my solution this way... I started at the top of the page and then rolled my mouse. My cousing was more creative and pressed page down. Quote Link to comment Share on other sites More sharing options...
JohnH Posted August 7, 2007 Report Share Posted August 7, 2007 I like Pacun's method the best. It's better to use the computer to solve a problem than to strain the brain with all that Algebra. Quote Link to comment Share on other sites More sharing options...
bstaxes Posted August 7, 2007 Report Share Posted August 7, 2007 Really liked the problem. My background is math so I solved it using algebra. S + L + P = 27 snakes, lizards, people number of heads 2P = L twice as many lizards as people 4L + 2P = 70 number of feet 4(2P) + 2P = 70 10P = 70 P = 7 2P = L 2(7) = L 14 = L S + 14 + 7 = 27 S = 6 Quote Link to comment Share on other sites More sharing options...
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