Question

The least number which when decreased by 7 is exactly divisible by 12, 16, 18, 21 and 28 is

• A. 1,012
• B. 1,008
• C. 1,015
• D. 1,022

Answer 1

The correct option is C 1,015

$|\underset{–}{212,16,18,21,}28$
$|\underset{–}{76,8,9,21,}14$
$|\underset{–}{36,8,9,3,2}$
$|\underset{–}{22,8,3,1,2}$
$|\underset{–}{1,4,3,1,1}$
$LCM=2\times 7\times 3\times 2\times 4\times 3=1008$
Required number $=1008+7=1015$.