[tex]a) \\ \frac{3}{5} = \frac{a}{10} = > 3 \times 10 = 5 \times a \\ 30 = 5a \\ 6 = a \\ a = 6 \\ b) \\ \frac{24}{14} = \frac{b}{49} = > 24 \times 49 = 14 \times b \\ 1176 = 14b \\ 84 = b \\ b = 84[/tex]
[tex]c) \frac{c}{4} = \frac{12}{16} = > c \times 16 = 4 \times 12 \\ 16c = 48 \\ c = 3 \\ d) \frac{d + 3}{25} = \frac{3}{15} = > 15(d + 3) = 25 \times 3 \\ 15d + 45 = 75 \\ 15d = 75 - 45 \\ 15d = 30 \\ d = 2[/tex]