Questions

The alternation of wet and dry seasons leads to the leaching away of the siliceous matter of the rocks and the formation of laterite soils. It has been observed that there is a general relationship between altitude and the chemical composition of laterite soils. The soils on the higher areas are generally more acidic than on the low lying areas.

The inside of the bulb being a vacuum, the outside air rushes in when the bulb is broken. The vibrations of the rushing air molecules produce the sound.

The process of extensive planting of trees or seeds in barren lands to increase forest cover is called as Afforestation.

From the assumption and trial and error method,

last three digits sum must leave the same digit as the answer. It is possible only if the answer must be units digit number leaving tens digit as carry.

And the possible 3rd digit is 5. Since 5 + 5 + 5 = 15 

Now, 2nd step is  1 + x + x + x = 5

=> 3x = 4

It is possible with x = 8. 8 + 8 + 8 + 1 = 25 leaving 2 as carry. 

Now, 3rd step is 2 + x + x + x = 5 => x = 1

Hence, the three dgits are 1, 8, 5.

185 + 185 + 185 = 555.