Question

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

Answer 1

Step-by-step explanation:

Let the digit in the units place =x

Let the digit in the tens place =y

Then the 2-digit number is =10y+x

Sum of the digits of the number is 9

x+y=9

The number is 6 times the units digit.

So,

10y+x=6x

10y=5x

2y=x

Substitute x=2y in equation

2y+y=9

3y=9

y=3

x=2y

x=2×3=6

Now, the number is =10y+x

=30+6

=36

Answer 2

Given:

• Let the digit in the units place = x

• Let the digit in the tens place = y

Then the 2-digit number is = 10y + x

Sum of the digits of the number is 9

x + y = 9 --------------- (1)

The number is 6 times the units digit.

So,

10y + x = 6x

10y = 5x

2y = x ---------------- (2)

Substitute x = 2y in equation (1),

2y + y = 9

3y = 9

x = 2y

x = 2 × 3 = 6

Now, the number is = 10y + x

= 30 + 6

= 36