Algebra Math Question

Question

The sum of two numbers is 21. The first number is 2/5 of the second number. What are the numbers?

What is the smaller of the two numbers?______

What are the larger number of the two numbers?_____

Answer 1

The sum of two numbers is 21. The first number is 2/5 of the second number. What are the numbers?
What is the smaller of the two numbers?_6_____
What is the larger number of the two numbers?__15___

The equations are:

x+y = 21

x=(2/5)y

replacing x we obtain

(2/5)y + (5/5)y = 21

Y = 15

x=6

Answer 2

let x and y be the numbers

x+y=21

x=(2/5)y

substitute

(2/5)y+y=21

(1 2/5)y=21

(7/5)y=21

(5/7)(7/5)y=(5/7)21

y=15

x+15=21

x=6

check:

6+15=21

6/15=2/5