Question

Выполните действия 1)(8/25*15+1/20*4)*3/5 2)(3/14+2/21)*(5/13+5/39)

Answer 1

$1)( frac{8}{25} *15+ frac{1}{20} *4)* frac{3}{5} =( frac{8*3}{5} + frac{1}{5} )= frac{24+1}{5} = frac{25}{5} =5 \ \ 2)( frac{3}{14} + frac{2}{21} )*( frac{5}{13} + frac{5}{39} )=( frac{9}{42} + frac{4}{42} )*( frac{15}{39} + frac{5}{39} )=\\= frac{13}{42} * frac{75}{39} = frac{13*75}{42*39} = frac{1*75}{42*3} = frac{25}{42}$