Mark and Suzie are using a bucket to empty their flooded basement. Each bucket holds five cubic feet of water and it takes 112 f
ull buckets to completely empty all the water from the basement. If the basement is 14 feet wide and 20 feet long, how deep was the water when Mark and Suzie began their task?
2 answers:
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Answer:
Between 150 and 450
Step-by-step explanation:
We are going to find the number by resolving a system of linear equations.
First we write the system equations :
Where C : children, S : students and A : adults
The equation represents the ''full attendance''
The second equation :
This equation represents the totaled receipts.
The system :
has the following associated matrix :
By performing elementary matrix operations we find that the matrix is equivalent to
The new system :
Working with the equations :
Our solution vector is :
For example :
If 0 adults attended ⇒ A = 0
This verify the totaled receipts equation :
150($3)+600($5) = $ 3450
A ≥ 0 ⇒ If A = 0 ⇒ C = 150
C = 150 is the minimum children attendance
From the equation :
S ≥0
600 - 2A ≥ 0
600 ≥ 2A
300≥ A
A is restricted to the interval [ 0, 300]
When A = 0 ⇒ C = 150
When A = 300 ⇒C = 150 + A = 150 + 300 = 450
Children ∈ [ 150,450]
With C being an integer number (including 0)
Also S and A are integer numbers (including 0)