Here B=2,4,6,8....,200
Sum of elements in A∩B
=\underset{\mathrm{Multiple}\mathrm{of}2}{\underset{⏟}{(2+4+6+\ldots +200)}}-\underset{\mathrm{Multiple}\mathrm{of}2&3i.e.6}{\underset{⏟}{(6+12+\ldots +198)}}
-\underset{\mathrm{Multiple}\mathrm{of}5&2i.e.10}{\underset{⏟}{(10+20+\ldots +200)}}+\underset{\mathrm{Multiple}\mathrm{of}2,5&3i.e.30}{\underset{⏟}{(30+60+\ldots +180)}}
=2(2100×101)−6(233×34)−10(220×21)+30(26×7)
=5264