Math, asked by premahimmanamahin, 1 year ago

find the sum of all multiples of 7 between 500 and 900

Answers

Answered by naz12
18
a=504
l=896
d=7
an=a+ (n-1)d
896=504 + (n-1)7
392=(n-1)7
n-1=56
n=57

Sn=n/2(a+an)
57/2 ( 504 + 896)
57* 700=39900
Answered by cristal
10
a=504

an=896
d=7

sn = n/2(2a+(n-1)d)
     =896/2(2×504 +895×7
     =166(1008+2737)
      =166×3745
     =621670

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