Answer:
Let's call the number of boxes Maria started with:
There are 37 boxes
Explanation:
Let's call the number of boxes Kayla started with:
Then we can write:
22
=
b
+
7
2
Where:
22
is the number of boxes Kayla has left.
(
b
+
7
)
is the number of boxes Kayla started with plus the
7
she bought
The division by
2
represents
1
2
of the total boxes Kayla had being destroyed by fire.
We can solve this by first multiplying each side of the equation by
2
to eliminate the fraction while keeping the equation balanced:
2
×
22
=
2
×
b
+
7
2
44
=
2
×
b
+
7
2
44
=
b
+
7
Now, subtract
7
from each side of the equation to solve for
b
while keeping the equation balanced:
44
−
7
=
b
+
7
−
7
37
=
b
+
0
37
=
b
b
=
37
Kayla started out with 37 boxes.