Question

Intr-o curte sunt gaini si iepuri. In total sunt 43 capete si 124 picioare. Cate gaini si cati iepuri sunt in curte ?

Answer 1

43x2=86
124-86=38
38:2=19 iepuri
43-19=24 gaini

Answer 2

i- nr de iepuri
g- nr de găini
$\left \{ {{i+g=43} \atop {4i+2g=124}} \right.$
$\left \{ {i=43-g} \atop {4i+2g=124}} \right.$
$\left \{ {{i=43-g} \atop {4(43-g)+2g=124}} \right.$
$\left \{ {{i=43-g} \atop {172-4g+2g=124}} \right.$
$\left \{ {{i=43-g} \atop {2g=48}} \right.$
$\left \{ {{i=43-g} \atop {g=24}} \right.$
$\left \{ {{i=43-24} \atop {g=24}} \right.$
$\left \{ {{i=19} \atop {g=24}} \right.$