The probability of choosing one of them is 2 / 80 .
the probability of choosing
the other one is 1 / 79 .
The probability of both things happening is
(2/80) x (1/79) = 1/3160
2
4
7
÷
1
3
6
=
1
5
7
Explanation:
When you divide mixed fractions you first convert them to improper fractions. Further, dividing by a number
a
b
is equivalent to multiplying by its reciprocal i.e. for dividing by
a
b
, you multiply by
b
a
i.e. numerator and denominators reversed. Hence,
2
4
7
÷
1
3
6
=
2
×
7
+
4
7
÷
1
×
6
+
3
6
=
18
7
÷
9
6
=
18
7
×
6
9
=
2
18
7
×
6
1
9
=
2
×
6
7
=
12
7
=
1
×
7
+
5
7
=
1
5
7
I believe it would be (5 x 600)+(5x80) = 3400