Michaella presents

Katy went to buy presents for her 3 friends. She paid 1/4 of her savings for the gift for Kristy. She bought a present for Michaella with half of the remaining money. She paid €8 for a gift for Marta. How much did all the gifts for Katy's friends cost together? And how much was the gift for Kristy, and how much was the gift for Michaella?

Correct answer:

k =  5.3333
m =  8
x =  21.3333

Step-by-step explanation:


x=k+m+8
k = x/4
m = 1/2·(x-k)

k+m-x = -8
4k-x = 0
k+2m-x = 0

Pivot: Row 1 ↔ Row 2
4k-x = 0
k+m-x = -8
k+2m-x = 0

Row 2 - 1/4 · Row 1 → Row 2
4k-x = 0
m-0.75x = -8
k+2m-x = 0

Row 3 - 1/4 · Row 1 → Row 3
4k-x = 0
m-0.75x = -8
2m-0.75x = 0

Pivot: Row 2 ↔ Row 3
4k-x = 0
2m-0.75x = 0
m-0.75x = -8

Row 3 - 1/2 · Row 2 → Row 3
4k-x = 0
2m-0.75x = 0
-0.375x = -8


x = -8/-0.375 = 21.33333333
m = 0+0.75x/2 = 0+0.75 · 21.33333333/2 = 8
k = 0+x/4 = 0+21.33333333/4 = 5.33333333

k = 16/3 ≈ 5.333333
m = 8
x = 64/3 ≈ 21.333333

Our linear equations calculator calculates it.

Try another example


Did you find an error or inaccuracy? Feel free to write us. Thank you!







Tips for related online calculators
Do you have a system of equations and are looking for calculator system of linear equations?

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

Units of physical quantities:

Grade of the word problem:

Related math problems and questions: