Let t and p represent the numbers of turtles and pelicans, respectively.
... 2p + 4t = 114 . . . . . . . the number of legs is 114
... p + t = 34 . . . . . . . . . the number of animals is 34
Divide the first equation by 2 and subtract the second.
... (2p +4t)/2 - (p +t) = (114)/2 - 34
... t = 23 . . . . . . . . . . . . . . . . . . . . . . simplify
Then p = 34 - t = 11
There are 11 pelicans and 23 turtles.
_____
You can get to the same answer by considering the number of legs you would have if all the animals were pelicans. That would be 34*2 = 68. The is 46 fewer legs than there actually are. Each turtle that replaces one of those 34 pelicans adds 2 legs to the total, so to add 46 legs, we must replace 46/2 = 23 pelicans with turtles. That is, there are 23 turtles and 11 pelicans.
