Let $t$ be TNYWR.

Kolapo lists the four-digit positive integers that can be made using the digits 2, 4, 5, and 9, each once. Kolapo lists these integers in increasing order. What is the $t^{\text {th }}$ number in his list?
There are $4 \cdot 3 \cdot 2 \cdot 1=24$ integers that Kolapo can make using the digits 2, 4, 5, and 9 . These include $3 \times 2 \times 1=6$ integers beginning with 2 , and 6 integers beginning with 4 , and 6 integers beginning with 5 , and 6 integers beginning with 9 .

Since the answer to (b) is 16 , then $t=16$.

The 16th integer in Kolapo's list is in the third group (those beginning with 5), and is the 4 th largest integer in this group.

In increasing order, the integers beginning with 5 in Kolapo's list are 5249, 5294, 5429, $5492,5924,5942$.

Therefore, the 16th number is 5492 .

ANSWER: $120,16,5492$