va rog repede dau coroana

Răspuns:
a/b=9/5=>b=5a/9
b/c=18/25
(5a/9)/c=18/25
18c=25×5a/9
18c=1255a/9
9×18c=125a
162c=125a=>a/c=162/125
Explicație pas cu pas:
[tex]\frac{a}{b} = \frac{9}{5}\\ [/tex]
[tex]\frac{b}{c} = \frac{18}{25} \\ [/tex]
[tex]\implies \frac{a}{c} = \frac{a}{b} \cdot \frac{b}{c} = \frac{9}{5} \cdot \frac{18}{25} = \bf \frac{162}{125} \\ [/tex]