Weighing animals

$\text{suppose, L=lion; C=cow and D=deer}$

$\text{now,}$

$L+2D=360$ ..............................[1]

$L+C=1170$ ...............................[2]

$\text{by doing [2]-[1] ,we get,}$

$L+C-L-2D=1170-360$

or, $C-2D=810$ ...........................[3]

$\text{and }$

$2C+2D=2160$ .........................[4]

$\text{by doing [3]+[4], we get that,}$

$2C+2D+C-2D=2160+810$

or, $C=990$

$\text{by putting this value in [2] and then [1],we get that,}$

$D=90 and L=180$

so, $L+C+D=180+990+90$ = $\boxed{1260}$

$L=lion,D=deer,C=cow$

$L+2D=360$ $\implies$ $\boxed{1}$

$C+L=1170$ $\implies$ $\boxed{2}$

$2D+2C=2160$ $\implies$ $\boxed{3}$

Solve for $L$ in terms of variable in $\boxed{1}$ and $\boxed{2}$ , then equate, we get

$C-2D=810$ $\boxed{4}$

add $\boxed{3}$ and $\boxed{4}$ , we get

$C=990$

It follows that,

$L=1170-990=180$

and

$D=\dfrac{360-180}{2}=90$

Finally,

$C+D+L=990+90+180=$ $\boxed{1260}$