Question

Uppose a computer processor can perform about 3.8 billion operations per second. how many operations can it perform in 0.6 ​second?

Answer 1

We have information:
3.8 billion         1 second
x billion            0.6 second

To find out the number of operations we need to cross multiply these equations and solve for x.
3.8 * 0.6 = 1*x
x = 2.28 billion

In 0.6s computer can do 2.28 billion operations.

Answer 2

Actually, this is basically a math question: 

if during one uni (1 second) 3.8 billion things (here operations) will happen, then how many will happen in 0.6 of the unit (here seconds)

We need to multiply 3.8 (let's keep the "billion" for later, like a unit)

$\frac{6}{10} *3.8=6*0.38=0.38=2.28$

So the answer is: 2.28 billion operations can be performed in 0.6 seconds.