Bài 1:
Chiều rộng hcn đó là:
\(\dfrac{4}{3}\times\dfrac{1}{2}=\dfrac{2}{3}\) ( m )
Chu vi hình chữ nhật đó là:
\(\left(\dfrac{4}{3}+\dfrac{2}{3}\right)\times2=4\left(m\right)\)
Đ/s: 4 m
Bài 2:
\(\dfrac{2}{5}+\dfrac{1}{3}:\dfrac{2}{3}=\dfrac{2}{5}+\dfrac{1}{3}\times\dfrac{3}{2}=\dfrac{2}{5}+\dfrac{1}{2}=\dfrac{4}{10}+\dfrac{5}{10}=\dfrac{9}{10}\)
Bài 3;
\(\Rightarrow\dfrac{3}{4}+x\times\dfrac{5}{2}=\dfrac{37}{16}\\ \Rightarrow x\times\dfrac{5}{2}=\dfrac{37}{16}-\dfrac{3}{4}=\dfrac{25}{16}\\ \Rightarrow x=\dfrac{25}{16}\times\dfrac{2}{5}=\dfrac{5}{8}\)
Bài 4:
\(\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}=\dfrac{15}{16}\)
Bài 5:
\(\Rightarrow x\times\dfrac{2}{5}=\dfrac{4}{7}\\ \Rightarrow x=\dfrac{4}{7}\times\dfrac{5}{2}=\dfrac{10}{7}\)
