Question

The product of two whole numbers is 416 and their sum is 42. What are the two numbers?

Answer 1

Answer:

The two numbers are 16 and 26.

Step-by-step explanation:

We can solve this question using 2 simultaneous equations based on the given information from the question.

Let number 1 = x

Let number 2 = y

xy = 416 -> ( 1 )

x + y = 42 -> ( 2 )

We can use either substitution or elimination to solve simultaneous equations. For this question, we will use substitution as it is the easier and shorter option.

Make y the subject in ( 2 ):

x + y = 42 -> ( 2 )

y = 42 - x -> ( 3 )

Substitute ( 3 ) into ( 1 ):

xy = 416 -> ( 1 )

x ( 42 - x ) = 416

42x - x^2 = 416

-x^2 + 42x - 416 = 0

- [ x^2 - 42x + 416 ] = 0

- [ x^2 - 16x - 26x + 416 ] = 0

- [ x ( x - 16 ) - 26 ( x - 16 ) ] = 0

- ( x - 16 ) ( x - 26 ) = 0

x = 16 -> ( 4 ) , x = 26 -> ( 5 )

Substitute ( 4 ) into ( 3 ):

y = 42 - x -> ( 3 )

y = 42 - ( 16 )

y = 26

Substitute ( 5 ) into ( 3 ):

y = 42 - x -> ( 3 )

y = 42 - ( 26 )

y = 16

Therefore:

x = 16 , y = 26

x = 26 , y = 16

The two numbers are 16 and 26.