\[\boxed{\mathbf{346\ (346).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[Цена\ (руб.)\] | \[Количество\ (кг)\] | \[Стоимость\ (руб.)\] |
---|---|---|
\[70\frac{2}{5}\] | \[6\frac{1}{4}\] | \[?\] |
Решение.
\[6\frac{1}{4}\ кг\ конфет.\]
\[Ответ:440\ рублей.\]
\[\boxed{\mathbf{346}\mathbf{.}}\]
\[1)\ \frac{4}{7} \cdot \frac{3}{5} = \frac{4 \cdot 3}{7 \cdot 5} = \frac{12}{35}\]
\[2)\ \frac{8}{27} \cdot \frac{3}{4} = \frac{8 \cdot 3}{27 \cdot 4} = \frac{2}{9}\]
\[3)\ 9\frac{3}{5} \cdot \frac{10}{21} = \frac{48}{5} \cdot \frac{10}{21} = \frac{48 \cdot 10}{5 \cdot 21} =\]
\[= \frac{16 \cdot 2}{1 \cdot 7} = \frac{32}{7} = 4\frac{4}{7}\]
\[4)\ 1\frac{5}{7} \cdot 6\frac{1}{8} = \frac{12}{7} \cdot \frac{49}{8} = \frac{12 \cdot 49}{7 \cdot 8} =\]
\[= \frac{3 \cdot 7}{1 \cdot 2} = \frac{21}{2} = 10\frac{1}{2}\]
\[5)\ 4\frac{1}{2} \cdot 3\frac{1}{3} = \frac{9}{2} \cdot \frac{10}{3} = \frac{9 \cdot 10}{2 \cdot 3} =\]
\[= 3 \cdot 5 = 15\]
\[6)\ 2\frac{1}{4} \cdot \frac{16}{27} \cdot 4\frac{1}{3} = \frac{9}{4} \cdot \frac{16}{27} \cdot \frac{13}{3} =\]
\[= \frac{9 \cdot 16 \cdot 13}{4 \cdot 27 \cdot 3} = \frac{1 \cdot 4 \cdot 13}{1 \cdot 3 \cdot 3} = \frac{52}{9} =\]
\[= 5\frac{7}{9}\]