A watch gains 10 seconds for every two hours. It was set right on Tuesday at 9:45am, what time did it show on Friday at 9:45 am?

9:51 am

Step-by-step explanation:

Here, we want to know what a faulty wrists watch will read.

The first thing to do is to know the number of hours between the hours given.

Since it is from Tuesday to Friday, the number of hours is 72 hours (3 days)

So the number of two hours here is 36

Now for all these 36, there is a gain of 10 seconds for each

The total gain in seconds will be 36 * 10 = 360 seconds which is same as 6 minutes

So the time it will read will be 45 + 6 = 51 minutes

Time shown is thus 9:51 am