$C_{7}H_{16}:a$

$C_8H_{18}:5a$

$C_9H_{20}:3a$

$C_{10}H_{22}:a$

`=>`$V_{xăng}=22.4(a+5a+3a+a)=22.4 \times 10a(L)$

Dùng bảo toàn $e:$

$(7 \times 4+16)a+(8 \times 4+18) \times 5a+(9 \times 4+20) \times 3a+(10 \times 4+22)a=4n_{O_2}$

`=>`$524a=4n_{O_2}$

Giả sử $V_{O_2}=\dfrac{V_{kk}}{4}$

`=>`$V_{kk}=4n_{O_2} \times 22.4=524a \times 22.4(L)$

`=>`$V_{xăng}:V_{kk}=\dfrac{22.4 \times 10a}{22.4 \times 524a}=\dfrac{5}{262}$