Question

x+x+4+x+8+x+12+...+x+400=21917
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Answer 1

x+x+4+x+8+x+12+...+x+400=21917

x+ x+1.4+x+2.4+x+3.4+...+x+100.4= 21917

x+(x+x+..+x) + 4(1+2+3+...+100)=21917

x+ 100x + 4 [(100)(101)/2] = 21917

101x + 20020 = 21917

101x = 1717

x = 1717/101

x = 17