Question
If the 5-digit number 693XY is divisible by 3, 7, and 11,
then what is the value of X + 2Y?Solution
ATQ;
The 5-digit number 693XY is divisible by 3, 7, and 11.
Divisibility rule of 3: The sum of digits must be a multiple of 3.
6+9+3+X+Y=18+X+Y
So, X + Y must be one of {0, 3, 6, 9, 12, 15, 18}.
Divisibility rule of 11: The difference between the sum of alternate digits must be divisible by 11.
(6+3+Y)β(9+X)=0
9+Yβ9βX=0
YβX=0
X=Y
From X + Y = 6, and X = Y, we get:
2X=6βX=3,Y=3
Checking divisibility by 7:
The number 69333 is divisible by 7.
Finding X + 2Y:3+2(3)=3+6=9
A pond of water appears less deep due to β
Which law states that the ratio of the potential difference across a conductor to the current through it is constant, provided the temperature remains c...
When white light passes through a glass prism, which color deviates the least?

The weight (W) of a body is derived from which formula?
What is the momentum of a 2 kg object moving at 3 m/s?Β Β
In an experimental arrangement of a Fresnel's biprism, monochromatic light of wavelength 2. is used to produce interference fringe pattern. On introduc...
Parsec is the unit of
Match the following machines with their working principles:
(i) Electric motor -Β (a) Heat energy into mechanical energy
(ii) Steam engin...
What happens to the electrostatic force between two charges when the distance between them decreases?Β