Find the total number of parts in the following ratios:
$2:3$2:3
$7:17$7:17
$73:53$73:53
$5:7:9$5:7:9
$20$20 is divided into two parts, $A$A and $B$B, in the ratio $2:3$2:3.
$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.