Bạn tham khảo nhé!
$a$ $:$ $b$ $:$ $c$ $:$ $d$ $=$ $2$ $:$ $5$ $:$ $8$ $:$ $15$ và $a$ $+$ $b$ $+$ $c$ $+$ $d$ $=$ $90$
Ta có : $a$ $:$ $b$ $:$ $c$ $:$ $d$ $=$ $2$ $:$ $5$ $:$ $8$ $:$ $15$
$→$ $\dfrac{a}{2}$ $=$ $\dfrac{b}{5}$ $=$ $\dfrac{c}{8}$ $=$ $\dfrac{d}{15}$
Áp dụng t/c dãy tỉ số $=$ nhau ta có :
$\dfrac{a}{2}$ $=$ $\dfrac{b}{5}$ $=$ $\dfrac{c}{8}$ $=$ $\dfrac{d}{15}$ $=$ $\dfrac{a+b+c+d}{2+5+8+15}$ $=$ $\dfrac{90}{30}$ $=$ $3$
$→$ $\dfrac{a}{2}$ $=$ $3$ $→$ $a$ $=$ $6$
và $\dfrac{b}{5}$ $=$ $3$ $→$ $b$ $=$ $15$
và $\dfrac{c}{8}$ $=$ $3$ $→$ $c$ $=$ $24$
Và $\dfrac{d}{15}$ $=$ $3$ $→$ $d$ $=$ $45$
Vậy $a$ $=$ $6$ $;$ $b$ $=$ $15$ $;$ $c$ $=$ $24$ và $d$ $=$ $45$
$FbBbinhne2k88$
