UPSEE 2017 Solved Paper

The particle of mass 2‌mathrm‌~kg is situated perpendicular to the axis of rotation. So, the angle will be 90°.
Similarly, the particle of mass 1kg is situated opposite side of the circular path. So, the angle will be 90° and angular momentum will acts in opposite direction.
According to the diagram, total angular momentum=2×2×2‌sin‌90°+3×3×3‌sin‌0° −1×1×1‌sin‌90°
=8−1
=7kgm2∕s [∵sin‌0°=0 and sin‌90°=1]