Question

Tìm x: a) x :\(3\frac{1}{15}=1\frac{1}{12}\)     b) x+\(15\%\cdot x=115\)   

Tính:   a) \(\frac{41}{42}+\frac{55}{56}+\frac{71}{72}+\frac{89}{90}\)

Answer 1

\(Tìmx:\)

\(a.x:3\frac{1}{15}=1\frac{1}{12}.\)

        \(x:\frac{46}{15}=\frac{13}{12}.\)

                 \(x=\frac{13}{12}.\frac{46}{15}.\)

                  \(x=\frac{299}{90}.\)          

\(Tính:\)

\(a.\frac{41}{42}+\frac{55}{56}+\frac{71}{72}+\frac{89}{90}BCNN=2520.\)  \(=\frac{2460}{2520}+\frac{2475}{2520}+\frac{2485}{2520}+\frac{2492}{2520}.\)

\(=\frac{9912}{2520}.\)

\(=\frac{59}{15}.\)

CÂU B CỦA BÀI TÌM X MÌNH CHƯA HỌC NÊN KO BÍT LÀM!

Answer 2

a) x : \(3\frac{1}{5}=1\frac{1}{12}\)

x : \(\frac{16}{5}=\frac{13}{12}\)

x = \(\frac{13}{12}.\)\(\frac{16}{5}\)

x = \(\frac{208}{60}=\frac{52}{15}\)

b) x + 15% . x = 115

x + \(\frac{3}{20}\).x = 115

x.1 + \(\frac{3}{20}.x=115\)

x. (1+\(\frac{3}{20}\))=115

x. \(\frac{23}{20}=115\)

x = \(115:\frac{23}{20}\)

x=100