Answer
a) $1/36$
b) $1/36$
c) $1/6$
Work Step by Step
The numbers on each number cube are $1, 2, 3, 4, 5,$ and $6$.
a)
P(red 1 and yellow 1)
$1/6 * 1/6 = 1/36$
b)
P(red 2 and yellow 2)
$1/6 * 1/6 = 1/36$
c)
P(red 1 and yellow 1) + P(red 2 and yellow 2) + P(red 3 and yellow 3) + P(red 4 and yellow 4) + P(red 5 and yellow 5) + P(red 6 and yellow 6)
$1/6 * 1/6 + 1/6 * 1/6 + 1/6 * 1/6 + 1/6 * 1/6 + 1/6 * 1/6 + 1/6 * 1/6$
$1/36 + 1/36 + 1/36 + 1/36 + 1/36 + 1/36$
$6/36 = 1/6$