Length of the room = 8m 25cm = 825 cm
Breadth of the room = 6m 75cm = 675 cm
Height of the room = 4m 50cm = 450 cm
Prime factorization of 825, 675 and 450 are as follows:
825 = 3×5×5×11
675 = 3×3×3×5×5
450 = 2×3×3×5×5
Common factors = 3×5×5
H.C.F. = 75
Hence, H.C.F. of 825, 675 and 450 is 75.
Therefore the length of the longest tap is 75 cm which can measure the three dimensions of the room exactly.

Lignite coal, is the lowest grade coal with the least concentration of carbon.

A plane mirror produces an image which will be laterally inverted.

So, the left side will appear right and right side will appear left.

3:25 means the hour hand is between 3 and 4.

Hence, 3 will appear as 8 and 25 will appear as 35. So, the time will be 8.35