Đáp án:
$1384$.
Giải thích các bước giải:
a) $3\dfrac45:48\dfrac{8}{15}=0,25:x$
$\Rightarrow \dfrac{19}{5}:\dfrac{728}{15}=\dfrac14:x\\\Rightarrow \dfrac{57}{728}=\dfrac14:x\\\Rightarrow x=\dfrac{182}{57}$
Vậy $x=\dfrac{182}{57}$.
b) $\dfrac23:0,4=x:\dfrac45$
$\Rightarrow\dfrac23:\dfrac25=x:\dfrac45\\\Rightarrow \dfrac53=x:\dfrac45\\\Rightarrow x=\dfrac43$
Vậy $x=\dfrac43$.