Question

4. Sum of the digits of a two-digit number is 5. First digit is one greater than the second. Find the number.
5. A number consists of two digits. If the digits interchange their places and the new number is added to the
original number, then the number becomes two times of the original number. Find the number.
6. The sum of the digits of a two-digit number is 17 and the difference between the digits is 1. What is the two-
digit number?​

Answer 1

Answer:

4. 32

5. Multiple of 11(e.g. 11,22,33,44,...)

6. 98

Step-by-step explanation:

4. ?+? = 5

Let the second number be x

So,

(x+1) + x = 5

= 2x + 1 = 5

= 2x = 5 - 1

= 2x = 4

x = 4 divided by 2

x = 2

second digit = 2

first digit = 2 + 1 = 3

32

5. Let the ten's digit be x and unit's digit be y.

Then, number = 10x + y.

Number obtained by interchanging the digits = 10y + x.

∴ (10x + y) + (10y + x) = 11(x + y), which is divisible by 11.

Multiple of 11

6. ? + ? = 17

Let the second digit be x

Let the first digit be x + 1

x + (x+1) = 17

2x + 1 = 17

2x = 17 - 1

2x = 16

x = 16 divided by 2

x = 8

First digit = 8 plus 1

98

Verification = 9 + 8 = 17

9 - 8 = 1

Answer 2

Answer:

let x,y be digits

x+y=5

x=y+1

put this value of x in above equation

y+1+y=5

2y+1=5

2y=5-1=4

y=2

x=y+1=2+1=3

Number=10x+y

=10*3+2=32ans