Question

The sum of two numbers is 30. The first number is twice the second number. what are the numbers?

Answer 1

x+y=30
x=2y
Substitute and you get
3y=30

y=10
x=20

Answer 2

Solve the following for x and y:\[\{x+y=30,x=2y\}\]\[\{x=20,y=10\} \]

Answer 3

the first number which is twice the second one is 10.. because if you double 10 it equals 20 , and you have 10 more to add to make it 30.