ind all possible values of x for which the number 7x3 is divisible by 3.

Question:

ind all possible values of x for which the number 7x3 is divisible by 3. Also, find each such number.

Solution:

For a number to be divisible by 3, the sum of the digits must be divisible by 3.

Sum of the digits $=7+x+3$

$=10+x$

$10+x$ will be divisible by 3 in the following cases:

$10+x=12$, or $x=2$

Thus, the number will be 723 .

$10+x=15$, or $x=5$

Thus, the number will be 753 .

$10+x=18$, or $x=8$

Thus, the number will be 783 .

So, the numbers can be 723, 753 or 783.

 

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