a number consist of 2 digits whose sum is 11. the number formed by reversing the digit is 9 less than the original number. find the number?
Answers
a number consist of 2 digits whose sum is 11. the number formed by reversing the digit is 9 less than the original number. find the number?
Let the tens digit be and the units digit be y. Then the number is 10x+y.
Sum of the digits is x+y=11.
The number formed by reversing the digits is 10y+x.
Given data, (10x+y)−9=10y+x
⇒10x+y−10y−x=9
9x−9y=9
Dividing by 9 on both sides, x−y=1 ........ (2)
Equation (2) becomes x=1+y .......... (3)
Substituting x in (1) we get, 1+y+y=11
⇒2y+1=11
2y=11−1=10
∴y=
2
10
=5
Substituting y=5 in (3) we get, x=1+5=6
∴ The number is 10x+y=10(6)+5=65
Concept:
First order equations include linear equations. In the coordinate system, the linear equations are defined for lines. A linear equation in one variable is one in which there is a homogeneous variable of degree 1 (i.e., only one variable). Multiple variables may be present in a linear equation. Linear equations in two variables, for example, are used when a linear equation contains two variables. Examples of linear equations include 2x - 3 = 0, 2y = 8, m + 1 = 0, x/2 = 3, and 3x - y + z = 3.
Given:
A number consist of 2 digits whose sum is 11. the number formed by reversing the digit is 9 less than the original number.
Find:
Find the number?
Solution:
Let the tens digit be and the units digit be y. Then the number is 10x+y.
Sum of the digits is x+y=11.
The number formed by reversing the digits is 10y+x.
Given data, (10x+y)−9=10y+x
⇒10x+y−10y−x=9
9x−9y=9
Dividing by 9 on both sides, x−y=1 ........ (2)
Equation (2) becomes x=1+y .......... (3)
Substituting x in (1) we get, 1+y+y=11
⇒2y+1=11
2y=11−1=10
∴y=10/2=5
Substituting y=5 in (3) we get, x=1+5=6
∴ The number is 10x+y=10(6)+5=65
Therefore, the number is 65
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