If an integer is divisible by 9, then the sum of its digits is divisible by 9. If the 7-digit integer 1,22X,333 is divisible by 9, what digit does X represent?
2007-10-27 13:28:06 · 4 answers · asked by utkarsh m 1 in Science & Mathematics ➔ Mathematics
First add 1+2+2+3+3+3
This gives 14.
Now, what is divisible by 9? 9, 18, 27... etc.
So we need to add a number to 14 to make it one of these.
14 + 4 = 18
14 + 13 = 27
Since it's a single number, we have 4 as our answer.
Hope that helped.
2007-10-27 13:31:20 · answer #1 · answered by monomat99 3 · 0⤊ 0⤋
1+2+2+x+3+3+3 = (14 + x)/9 = whole number
so x = 4
2007-10-27 20:39:32 · answer #2 · answered by 1294 4 · 0⤊ 0⤋
3+3+3 = 9 so all we need is 1+2+2+x = 9
So x = 4.
2007-10-27 20:33:56 · answer #3 · answered by steiner1745 7 · 0⤊ 0⤋
7
2007-10-27 20:32:03 · answer #4 · answered by ♪audrey♪ 4 · 0⤊ 2⤋