A computer can execute 36 instructions per microsecond.

How many instructions can it execute in 4 min?

36/microsec.

36/microsec x (10^6 microsec/sec) x ((60 sec/min) x 4 min = 8 something times 10^9.
or you can look here.
http://www.algebra.com/algebra/homework/Length-and-distance/Length-and-distance.faq.question.67226.html

To determine the number of instructions a computer can execute in 4 minutes, we can start by converting the given time from minutes to microseconds.

1 minute = 60 seconds
1 second = 1,000,000 microseconds

Therefore, 1 minute = 60 * 1,000,000 microseconds = 60,000,000 microseconds.

Next, we need to calculate the total number of microseconds in 4 minutes:

4 minutes = 4 * 60,000,000 microseconds = 240,000,000 microseconds.

Now that we have the total number of microseconds, we can calculate the number of instructions the computer can execute:

36 instructions/microsecond * 240,000,000 microseconds = 8,640,000,000 instructions.

Therefore, a computer can execute 8,640,000,000 instructions in 4 minutes.