find the sum of integers between 10 and 500 which is divisible y7
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1st integer which is divisible by 7 is 14...and last is 497.
1st we have to find number of terms..,
an=a+(n-1)d.a=7 an=497 d=7.
497=14+ (n-1)7
497/7=14+(n-1)
71= 14+(n-1)
71-14=n-1
56=n-1
n=55
now sum of the 55terms.,
sn =n/2(2a+(n-1)d)
s55=55/2(2×14+(55-1)7)
s55=55/2(28+378)
s55=55/2×406
s55=11165.that's it
1st we have to find number of terms..,
an=a+(n-1)d.a=7 an=497 d=7.
497=14+ (n-1)7
497/7=14+(n-1)
71= 14+(n-1)
71-14=n-1
56=n-1
n=55
now sum of the 55terms.,
sn =n/2(2a+(n-1)d)
s55=55/2(2×14+(55-1)7)
s55=55/2(28+378)
s55=55/2×406
s55=11165.that's it
Mithunmathew:
hi
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