Explanation

Number of tiles on one side of the room = 21 tiles.

Total tiles = B21×4= 84.

Since 4 tiles at each corner are shared by both rows, subtract these: 84−4= 80 tiles.

Explanation

Men days

60 : 40

40 : x           

60/40= x/40,     40x= 60* 40

x= 40*60/40,      x= 60

Explanation

You are now facing in the South direction

Explanation

Let's break down the movements step by step:

East 10 meters:

You are now 10 meters east of your house from the starting point.

North 15 meters:

Now you're 10 meters east and 15 meters north of your house.

West 12 meters:

Moving west by 12 meters puts you 2 meters west of your house (because 12 - 10 = 2).

South 15 meters:

Moving south 15 meters brings you back to your house's north-south position (because 15 meters north - 15 meters south = 0).

So now you're 2 meters west and 0 meters north-south from your house.

The distance from your house is simply 2 meters.

Explanation

B alone can complete the work in 20 days, so B's work rate is 1/20 of the work per day.

A and B together can complete the work in 15 days, so their combined work rate is 1/15 of the work per day.

Since B's work rate is 1/20, A's work rate can be found by subtracting B's work rate from their combined work rate: (1/15 - 1/20) = 1/60 of the work per day.

Therefore, A alone can complete the work in 60 days.

So, the correct answer is: 60 days.