How many parts are there in the ratio $20:3$20:3?
$20$20 is divided into two parts, $A$A and $B$B, in the ratio $3:2$3:2.
$25.9$25.9 is divided into two parts, $A$A and $B$B, in the ratio $5:2$5:2.
Johan and Wissam share $£112$£112 in the ratio $3:5$3:5.