Question

[Nhan Thanh]

1.a)Tính 12,5% của :

\(A=\dfrac{\left(85\dfrac{7}{30}-83\dfrac{5}{18}\right)\div2\dfrac{2}{3}}{0,04}\)

b) Tính 5% của :

\(B=\dfrac{\left(6\dfrac{3}{5}-3\dfrac{3}{14}\right).5\dfrac{5}{6}}{\left(21-1,25\right)\div2,5}\)

2. Tìm 12% của tổng \(\dfrac{3}{4}\)M+\(\dfrac{1}{3}\)N , biết :

\(M=\dfrac{3\div\dfrac{2}{3}-0,09\div\left(0,15\div2\dfrac{1}{2}\right)}{0,32.6+0,03-\left(5,3-3,88\right)+0,67}\)

\(N=\dfrac{\left(2,1-1,965\right)\div\left(1,2.0,045\right)}{0,00325\div0,013}-\dfrac{1\div0,25}{1,6.0,625}\)

Answer 1

[Nguyễn Lê Phước Thịnh]

Bài 1: 

a: \(A=\dfrac{\left(85+\dfrac{7}{30}-83-\dfrac{5}{18}\right):\dfrac{8}{3}}{\dfrac{1}{25}}\)

\(=\left(2+\dfrac{7}{30}-\dfrac{5}{18}\right)\cdot\dfrac{3}{8}\cdot25\)

\(=\dfrac{180+21-25}{90}\cdot\dfrac{75}{8}\)

\(=\dfrac{176}{90}\cdot\dfrac{75}{8}=\dfrac{55}{3}\)

=>12,5% của A là 55/8x1/8=55/64

b: \(B=\dfrac{\left(6+\dfrac{3}{5}-3-\dfrac{3}{14}\right)\cdot\dfrac{36}{5}}{19.75:2.5}\)

\(=\dfrac{\left(3+\dfrac{27}{70}\right)\cdot\dfrac{36}{5}}{\dfrac{79}{10}}\)

\(=\dfrac{\dfrac{210+27}{70}\cdot\dfrac{36}{5}}{\dfrac{79}{10}}\)

\(=\dfrac{4266}{175}\cdot\dfrac{10}{79}=\dfrac{108}{35}\)

=>5% là 108/35x1/20=27/175