find the sum of all three digit number which all divisible by 3 but not divisible by 5
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Answered by
1
102 are the answer of this
thxx
so much
so please mark as brain liest
to begin with 333 is divisible by 3 and not 5 and 333 is only one of many so how can the sum be 102
but always find3 digit smallest no okay
find the sum of ALL THREE DIGIT NUMBERS
means if find or solve and digit no so first of all starting from smallest no
there is no option of brainliest
means which 3 digit no
dont make me maid okay and please dont distrub me if you have any questions so please asked me
Answered by
2
The three digit numbers divisible by 3 form an AP with first term 102, last term 999 and common difference 3
So 999=102+(n-1)3
3n = 999-102+3 = 900
So n=300
Sum of all numbers= 300/2(102+999)
= 1,65,150
But this sequence also has some numbers which are multiples of 5 . These numbers will be multiples of 15 as the lcm of 3 and 5 is 15.
So these numbers also form an AP with first term 105, last term 990 and common difference 15
990=105+(n-1)15
15n = 990 -105+15=900
n=60
So sum = 60/2(105+990) = 32,850
So the required sum= 1,65,150 - 32,850
= 1,32,300
So 999=102+(n-1)3
3n = 999-102+3 = 900
So n=300
Sum of all numbers= 300/2(102+999)
= 1,65,150
But this sequence also has some numbers which are multiples of 5 . These numbers will be multiples of 15 as the lcm of 3 and 5 is 15.
So these numbers also form an AP with first term 105, last term 990 and common difference 15
990=105+(n-1)15
15n = 990 -105+15=900
n=60
So sum = 60/2(105+990) = 32,850
So the required sum= 1,65,150 - 32,850
= 1,32,300
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