A submarine submerges at the rate of $5 \mathrm{m}/\min$. If it descends from $20 \mathrm{m}$ above the sea level, how long will it take to reach $250 \mathrm{m}$ below sea level?

If, in a two-digit number, the digit at unit place is $x$ and the digit at tens place is $4$, then the two-digit number is _____.

Consider a three-digit number with the following properties:

I. If its digits in units place and tens place are interchanged, the number increases by $36$
II. If its digits in units place and hundreds place are interchanged, the number decreases by $198$ .

Now, suppose that the digits in tens place and hundreds place are interchanged. Then, the number

Write the regular form:

The sum of a $2$-digit number and the number formed by reversing its digits is $77$. What are the possible numbers satisfying this condition?

Following questions are based on the five three digit numbers given below :

$369, 274, 853, 219, 758$

One is subtracted from the first digit and two is subtracted from the third digit of each of the number. What will be the difference between the first digit of the highest number and the third digit of the lowest number ?

Following question are based on the five three- digit numbers given below :

$369, 274, 853, 219, 758$

If all the digits in each of the number are arranged in descending order within the number, which of the following will be the lowest number in the new arrangement of number?