Có : 990 ml + 9 ml + 1 ml = 1000 ml = 1 l

Vậy chọn B.

B.1

\(\dfrac{x}{8}\) + \(\dfrac{2}{3}\) = \(\dfrac{7}{6}\)

 \(\dfrac{x}{8}\)        = \(\dfrac{7}{6}\) - \(\dfrac{2}{3}\)

  \(\dfrac{x}{8}\)       = \(\dfrac{1}{2}\) 

   \(x\)        = \(\dfrac{1}{2}\) x 8 

    \(x\)       = 4

\(\dfrac{x}{8}+\dfrac{2}{3}=\dfrac{7}{6}\)

        \(\dfrac{x}{8}=\dfrac{7}{6}-\dfrac{2}{3}\)

        \(\dfrac{x}{8}=\dfrac{1}{2}=\dfrac{4}{8}\)

⇒ x = 4

Vậy x = 4

\(\overline{ab8}+\overline{ab}=949\\ \overline{ab}\times10+8+\overline{ab}=949\\\overline{ab} \times\left(10+1\right)=949-8\\ \overline{ab}\times11=941\\ \overline{ab}=941:11\\ \overline{ab}=941:11\\ \overline{ab}=\dfrac{941}{11}\) 

Mà: ab là số tự nhiên nên ta loại 

\(\dfrac{6}{8}=\dfrac{15}{x}\\ \Rightarrow6\times x=15\times8\\ \Rightarrow6\times x=120\\ \Rightarrow x=120:6\\ \Rightarrow x=20\)

Vậy \(x=20\)

Nhanh lên cíu tui v☹i

tớ chọn B

Bài giải:

Đổi: 7km 50m = 7 050m

Vì vậy 7km 50m < 7500m

Đáp án B

3,07 nhé!

Chi tiết hơn đc ko bạn

Câu 1:

\(\left(1\right)x\cdot1,5:2,4=0,3\\ x\cdot0,625=0,3\\ x=0,3:0,625\\ x=0,48\\ \left(2\right)\dfrac{3}{7}+\dfrac{1}{7}:x=1\\ \dfrac{1}{7}:x=1-\dfrac{3}{7}\\ \dfrac{1}{7}:x=\dfrac{4}{7}\\ x=\dfrac{1}{7}:\dfrac{4}{7}\\ x=\dfrac{1}{4}\\ O\left(3\right)\left(\dfrac{3}{4}\cdot31\dfrac{11}{23}+0,75\cdot\dfrac{12}{23}\right)\left(x-1\right)=24\\ \left(\dfrac{3}{4}\cdot31\dfrac{11}{23}+\dfrac{3}{4}\cdot\dfrac{12}{23}\right)\left(x-1\right)=24\\ \dfrac{3}{4}\cdot\left(31+\dfrac{11}{23}+\dfrac{11}{23}\right)\left(x-1\right)=24\\ \dfrac{3}{4}\cdot32\left(x-1\right)=24\\ 24\left(x-1\right)=24\\ x-1=1\\ x=2\\ \left(4\right)x-\dfrac{\dfrac{1}{3}-0,25+\dfrac{1}{5}}{1\dfrac{1}{6}-0,875+0,7}=2022\\ x-\dfrac{\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}}{\dfrac{7}{6}-\dfrac{7}{8}+\dfrac{7}{10}}=2022\\ x-\dfrac{\dfrac{2}{3}-\dfrac{2}{8}+\dfrac{2}{10}}{\dfrac{7}{6}-\dfrac{7}{8}+\dfrac{7}{10}}=2022\\ x-\dfrac{2\left(\dfrac{1}{3}-\dfrac{1}{8}+\dfrac{1}{10}\right)}{7\left(\dfrac{1}{6}-\dfrac{1}{8}+\dfrac{1}{10}\right)}=2022\\ x-\dfrac{2}{7}=2022\\ x=2022+\dfrac{2}{7}=\dfrac{14156}{7}\)