My work for your question
<h3>
Answer: 7/13</h3>
======================================================
Explanation:
We know that the marble selected is red, so we don't need to focus on the other colors.
7 red marbles are in urn B out of 2+7+4 = 13 total red marbles.
The probability the red marble came from urn B is therefore 7/13
Answer:
x
=
0
y
=
−
2
Explanation:
simply subtract each term in the second equation from the first equation:
3
x
+
4
y
=
−
8
3
x
+
16
y
=
−
32
(
3
x
−
3
x
)
+
(
4
y
−
16
y
)
=
(
−
8
−
(
−
32
)
)
(
0
)
+
(
−
12
y
)
=
(
−
8
+
32
)
−
12
y
=
24
y
=
−
2
now use either original equation to solve for
x
:
3
x
+
4
y
=
−
8
3
x
+
4
(
−
2
)
=
−
8
3
x
−
8
=
−
8
3
x
=
0
x
=
0