Question

If l:m=3/2:7/4 and m:n=7/3:21/5 find (1) l:n;(2) l:m:n.

Answer 1

$\frac{l}{m} = \frac{ \frac{3}{2} }{ \frac{7}{4} } = \frac{6}{7} = \frac{6 \times 5}{7 \times 5} = \frac{30}{35} \\ \frac{m}{n} = \frac{ \frac{7}{3} }{ \frac{21}{5} } = \frac{5}{9} = \frac{5 \times 7}{9 \times 7} = \frac{35}{63} \\ \frac{l}{n} = \frac{ \frac{l}{m} }{ \frac{m}{n} } = \frac{ \frac{30}{35} }{ \frac{35}{63} } = \frac{30}{63}$

Hence l:m:n = 30:35:63