Question

1) Tìm x

x - 35% . x = 1/25

2) Tính

a) 17 2/31 - ( 15/17 + 6 2/31 )

b) 27 51/59 - ( 25 51/29 - 1 1/3 )

c) ( 4 5/23 - 2 2/5 + 7 7/13 ) - ( 3 5/23 - 6 6/13 )

d) 8 1/3 + 7,8 + 5 2/3 - 1,8

Answer 1

Bài 1: 

Ta có: \(x-35\%\cdot x=\dfrac{1}{25}\)

\(\Leftrightarrow65\%\cdot x=\dfrac{1}{25}\)

\(\Leftrightarrow x=\dfrac{1}{25}:\dfrac{13}{20}=\dfrac{1}{25}\cdot\dfrac{20}{13}=\dfrac{4}{65}\)

Vậy: \(x=\dfrac{4}{65}\)

Answer 2

Bài 2: 

a) Ta có: \(17\dfrac{2}{31}-\left(\dfrac{15}{17}+6\dfrac{2}{31}\right)\)

\(=17\dfrac{2}{31}-\dfrac{15}{17}-6\dfrac{2}{31}\)

\(=11+\dfrac{2}{31}-\dfrac{15}{17}\)

\(=\dfrac{5366}{527}\)