Răspuns :
a·12=b·9=k
⇒a·12=k⇒a=k/12;
⇒b·9=k⇒b=k/9;
⇒x/100 ·b=a
⇒x/100 ·k/9=k/12
⇒x/100=k/12/k/9
⇒x/100=k/12·9/k
⇒x/100=1/4·3/1
⇒x/100=3/4
⇒x=100·3/4
⇒x=3/1·25/1
⇒x=75[la suta-din b reprezinta a];
⇒a·12=k⇒a=k/12;
⇒b·9=k⇒b=k/9;
⇒x/100 ·b=a
⇒x/100 ·k/9=k/12
⇒x/100=k/12/k/9
⇒x/100=k/12·9/k
⇒x/100=1/4·3/1
⇒x/100=3/4
⇒x=100·3/4
⇒x=3/1·25/1
⇒x=75[la suta-din b reprezinta a];