Questions

Non collision can happen only when all the cars move in same direction.

That is either all cars moving in clockwise direction or all cars moving in anti clockwise direction.
P(all cars not colliding)

= P(all cars moving in the same direction)

= P(all cars moving in clockwise direction)  +  P(all cars moving in anticlockwise direction)

= [p(A --> C) x p(C --> B) x p(B --> A)]  +  [p(A --> B) x p(B --> C) x p(C --> A)]

= [1/2 x 1/2 x 1/2] + [1/2 x 1/2 x 1/2]

= 1/8 + 1/8

= 1/4

The collections of entities of a particular Entity Type are grouped together into an entity set.

The monomer of polythene is ethylene.

Let the Number be x. 

Given that one third of a Number is 96. 

i.e x = 3 x 96 = 288.

 67% of  x = x×67100=288×67100=192.96

Ozone molecule has one single bond and one double bond.