Explanation:
each combination of 2 specific numbers has the same probability. there is no difference in probability between the individual numbers.
remember, a probability is always desired cases over all possible cases.
we have 4 different possible outcomes every time we spin the spinner.
to get a specific number has the probability of 1/4, because we want 1 specific outcome, and have in total 4 different possibilities.
now, we spin a second time. the probability to get a specific number is again 1/4.
but, if we consider both events to be connected, when we want to know the probability to get 2 specific numbers when spinning twice, we have to multiply the individual probabilities :
1/4 × 1/4 = 1/16
so, the probability to land first on a 5, and then secondly on a 2 is 1/16.
the same as for landing first on a 3, and then on a 5.
the same as for landing first on a 4, and then on a 4 (again).
that is because the individual spin results are independent. the result of the first spin does not impact in any way the result of the second spin (in contrary to e.g. pulling multiple cards without returning the previously pulled cards).