$From$ $these$ $given$ $numbers$ $We$ $can$ $make$ $Composite$ $numbers$ $only$ $8,9,10, 12,14,16,18$
$2+7=9$
$3+5=8$
$3+7=10$
$3+11=14$
$5+7=12$
$5+11=16$
$11+7=18$
$2$ $can$ $Come$ $only$ $First$ $Or$ $Last$ $Position $ $Coz$ $if$ $it'll$ $come$ $in$ $middle$ $then$ $we$ $can't$ $make$ $Composite$ $number$ $with$ $the$ $consecutive$ $sum.$
$\underbrace{2 }$ __ __ __ __ $OR$ __ __ __ __ $\underbrace{2 }$
$7$ $Can$ $only$ $come$ $beside$ $2$
$2$ $7$ __ __ __ $OR$ __ __ __ $7$ $2$
$In$ $Remaining$ $3$ $places$ $3$, $5$, $11$ $can$ $come$ $3!$ $ways.$
$So$ $ultimately$ $these$ $Can$ $Come$ $2*1 *3!$ $=$ $12$
