(x+1)+(2x+3)+(3x+5)+...+(100x+199)=30200
=(x+2x+3x+..........+100x)+(1+3+5+......+199)=4950
=x.(1+2+3+.........+100)+(1+3+5+.......+199)=4950
=>5050x+10000=30200
=>5050x=30200-4950
=>5050x=25250
=>x=25250:5050
=>x=5
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