Question

the sum of two numbers is 30 and their difference is 4 find the numbers

Answer 1

let the numbers are x and y

if their sum is 30 and difference is 4

then

x+y=30     --------------1equation
x-y=4          -----------2equation

add both the equations,

2x=34

x=17

then 

put the value of x in 1equation,

x+y=30

17+y=30

y=30-17

y=13

then,

first number is 17 and second number is 13

Answer 2

Given,

Given that

                  x+y= 30

                  x-y =4

To find,

Find 'x' and 'y'.

Solution,

We can solve this problem by the following method:

Let 'x' and 'y' as two numbers

If,   x+y=30     __Equation (1)  

     x-y= 4       __Equation (2)

Then, combine the two equations

    x   + y        = +30

    x   - y         = +4    

  2x (+y-y=0) = +34

∴2x=34

  x=34 ÷ 2

    =17

Now, Substitute x as 17 in Equation (1) or Equation (2)

17+ y=30

∴y= 30-17

    = 13

Let's see if the values are correct or not by giving substitution in the remaining equation.

Here, Equation (2)

x=17, y=13

Now, 17-13=4

Thus, easy to check the answers.

Here, the numbers are 17 and 13.