Youngest sibling

Peter, Leo, and Ike are siblings. Peter is three times as old than Leo, and Leo is three times younger than Ike. They are 28 years old together.
How many years is the youngest of them?

Final Answer:

l =  4

Step-by-step explanation:


p = 3l
l = i/3
p+i+l=28

p = 3·l
l = i/3
p+i+l=28

3l-p = 0
i-3l = 0
i+l+p = 28

Pivot: Row 1 ↔ Row 2
i-3l = 0
3l-p = 0
i+l+p = 28

Row 3 - Row 1 → Row 3
i-3l = 0
3l-p = 0
4l+p = 28

Pivot: Row 2 ↔ Row 3
i-3l = 0
4l+p = 28
3l-p = 0

Row 3 - 3/4 · Row 2 → Row 3
i-3l = 0
4l+p = 28
-1.75p = -21


p = -21/-1.75 = 12
l = 28-p/4 = 28-12/4 = 4
i = 0+3l = 0+3 · 4 = 12

i = 12
l = 4
p = 12

Our linear equations calculator calculates it.



Help us improve! If you spot a mistake, please let let us know. Thank you!







Tips for related online calculators
Do you have a linear equation or system of equations and are looking for a solution? Or do you have a quadratic equation?
Do you want to convert time units like minutes to seconds?

You need to know the following knowledge to solve this word math problem:

algebrabasic operations and conceptsUnits of physical quantitiesGrade of the word problem

Related math problems and questions: