Gọi x, y là mol Mg, Ca.
$\Rightarrow 24x+40y=88$ (1)
$n_{O_2}=\dfrac{48}{32}=1,5 mol$
$2Mg+O_2\buildrel{{t^o}}\over\to 2MgO$
$2Ca+O_2\buildrel{{t^o}}\over\to 2CaO$
$\Rightarrow 0,5x+0,5y=1,5$ (2)
(1)(2)$\Rightarrow x=2; y=1$
$m_{Mg}=24.2=48g$
$m_{Ca}=40g$