Final answer:
the two numbers are 13 and 8. To find the two numbers, we can set up two equations based on the given information and solve them simultaneously.
Step-by-step explanation:
Let's assume the first number is x and the second number is y.
According to the given information, one number is 3 less than twice as big as the other number. This can be expressed as follows:
x = 2y - 3
The sum of the two numbers is 21, so we can write the equation:
x + y = 21
Substituting the value of x from the first equation into the second equation:
(2y - 3) + y = 21
Combining like terms:
3y - 3 = 21
Adding 3 to both sides:
3y = 24
Dividing both sides by 3:
y = 8
Substituting the value of y back into the first equation:
x = 2(8) - 3
x = 13
Therefore, the two numbers are 13 and 8.