Answer:
0.3 or 30%
Step-by-step explanation:
Since no innocent student will ever be caught, the probability that a student sends an email and/or text message during a lecture AND gets caught is given by the product of the probability of a student sending a message (60%) by the probability of the professor catching them (50%) :

The probability is 0.3 or 30%.
There are no real values for log of 0 or negatives.
So the answer is B
we know that
A quick way to estimate the sum of two numbers is to round each number and then add the rounded numbers
case a) We round the number to the nearest hundred
so
Round up is equal to 
Round up is equal to 
Find the estimate sum

case b) We round the number to the nearest tens
so
Round up is equal to 
Round down is equal to 
Find the estimate sum

There is no width to begin with.