find the sum of all integers between 50 an 500 divisible by 7
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The required A.P is
56, 63, 70,.........., 497
a = 56
d = T2 - T1
d = 63 - 56
d = 7
Tn = a +(n-1)d
497 = 56 + (n-1)7
497-56 = (n-1)7
441/7 = n-1
63 +1 = n
n = 64 terms
Sn = n/2 (a+l)
S 64 = 64/2 ( 56 + 497)
S 64 = 32 x 553
S 64 = 17,696
Hence the sum of all integers between 50 and 500 divisible by 7 is 17,696.
56, 63, 70,.........., 497
a = 56
d = T2 - T1
d = 63 - 56
d = 7
Tn = a +(n-1)d
497 = 56 + (n-1)7
497-56 = (n-1)7
441/7 = n-1
63 +1 = n
n = 64 terms
Sn = n/2 (a+l)
S 64 = 64/2 ( 56 + 497)
S 64 = 32 x 553
S 64 = 17,696
Hence the sum of all integers between 50 and 500 divisible by 7 is 17,696.
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