Questions

Probability of sending the correct material is 4/5

Probability of the material not being damaged in transit is 1/4

Probability that there is no short shipment = 2/3

∴ Required probability =4/5 x 1/4 x 2/3 = 2/15

Water has the maximum density at 4oC. So at this temperature, it sinks down to bottom and stays here. If it cools further, it will become less dense and move up. So while the upper layers can cool enough to form ice, the bottom layers remain as water at  4oC .  

Therefore, (C) is correct.

In the starting it is given that Couple went to the movie and No other went with them.

So total members went to movie is only 2.

The first step in the refining of petroleum is distillation i.e,  the fractionation of crude oil in atmospheric and vacuum distillation towers.

The first process petroleum refinery is known as distillation. In this process, crude oil is heated and fed into a distillation column. As the temperature of the crude oil in the distillation column rises, the crude oil separates itself into different components, called "fractions." The fractions are then captured separately. Each fraction corresponds to a different type of petroleum product, depending on the temperature at which that fraction boils off the crude oil mixture.