What is the total number of ducks?

Question

Out of a group of ducks, 7/2 times the square root of the number are swimming in water while two remaining are playing on the shore.
What is the total number of ducks?

Answer 1

the total numbers are 16,
because according to the ques
(7/2)*square root of 16 + 2=16

Answer 2

Let total ducks=X
let square root of X=Y
Y^2-7*Y/2=2
2*Y^2-7Y=4
2*Y^2-7Y-4=0
2*Y^2-8Y+Y-4=0
(2Y+1)(Y-4)=0
Y=4
Y^2=X=16
Total ducks=16