Question

S=15+16+......+200 S=200+201+.....+315 S=5+6+7+.....+300 S=101+102+.....+2018
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Answer 1

S=15+16+......+200

S=1+15+2+15+3+15+....+185+15

S = (1+2+3+...185)+15 x 185

S = 185 x 186/2+15 x 185

S = 185x 93+15 x 185

S= 185 x (93+15)

S = 185 x 104

S= 19 240

S=200+201+.....+315 S=5+6+7+.....+300

S= 1+199+2+199+3+199+4+199+....+101+199

S=( 1+2+3+4+...+101) + 101 x 199

S =101 x 102/2+101 x 199

S =101x51+101x199

S= 101 (51+199)

S = 101 x 250

S= 25 250

S=101+102+.....+2018

S= 1+100+2+100+3+100+...1918+100

S =( 1+2+3+4+....+1918) +1918 x 100

S= 1918x1919/2+1918 x 100

S= 1918(1919/2+100)