Question

The sum of a 2 digit number is 9 .The number is 6 times the units digit .Find the number

Answer 1

Define x & y:

The digit in the tens place is ‘x’.

The digit in the ones place is ‘y’.

The number is (10x+y).

From equation 1:

The sum of the digit is 9.

x+y=9

x=9-y

Form equation 2:

The number is 6 times the units.

10x+y=6

Put the equation together....

x=9-y ...(i)

10x+y=6y ...(ii)

Find y:-

Sub[1] into [2]

10(9-y)+y=6y

90-10y+y=6y

15y=90

y=90÷15

y=6

Find x:-

When y=6

x=9-6

x=3

Find the number...

The number =10x+y....

The number=10(3)+6....

The number=36

$Hence \: the \: number \: is \: 36</p><p>$