[tex] \frac{3a}{2b} = \frac{5}{3} [/tex]
[tex]3 \times 3a = 5 \times 2b[/tex]
[tex]9a = 10b[/tex]
[tex]a = \frac{10b}{9} [/tex]
[tex]5a + 2b = 204[/tex]
[tex]5 \times \frac{10b}{9} + 2b = 204[/tex]
[tex] \frac{50b}{9} + 2b = 204 \: | \times 9[/tex]
[tex]50b + 18b = 1836[/tex]
[tex]68b = 1836[/tex]
[tex]b = \frac{1836}{68} [/tex]
[tex]b = 27[/tex]
[tex]a = \frac{10b}{9} [/tex]
[tex]a = \frac{10 \times 27}{9} [/tex]
[tex]a = \frac{270}{9} [/tex]
[tex]a = 30[/tex]
[tex]a - b = 30 - 27 = 3[/tex]
