Answer:
9.75 hours
Step-by-step explanation:
If Rob drove 35% of the time and Mark drove the remainder of the time, the total is 100 %
100-35 = 65
so Mark drove 65% of the time
The total time driven was 15 hours, so we multiply the total time driven by the percentage of time that Mark drove to find the number of hours that Mark drove.
15 * 65%
15*.65
9.75 hours
I assume you are asking one of three things, so I will answer all of them.
if you are asking what is 1/2 of 312, then multiply 312 by 1/2. 312 is really just 312/1, so

we multiply fractions by multiplying straight across

if you were asking what part of 3 1/2 is 1/2 then we have to recognize what 3 1/2 is as an improper fraction. to do this, we convert 3 into halves. how many halves of pizza are there in 3 whole pizzas? 6. so we have 6 halves and one half, which is a total of 7 halves.

now, we do the same thing as the first problem

if you were asking what is half of 3.12, then we convert 1/2 to a decimal and multiply
Answer:
The answer is B. Between 4.5 and 6 hours since he started playing
Step-by-step explanation: