Expert: Josh - 6/27/2005

Question
Hi, I have this problem:

"A boy watches TV for 24 hours a week. On friday saturday and sunday he watched TV for twice as much as on monday, tuesday, wednesday and thursday. How long did he watch TV for each day?"

Okay I got this but I don't know how:

MTWT: 2H 24M
FSS: 4H 48M

For some reason I divided 24 by 10...

Sorry if this is out of your area of knowledge. Thanks.

Answer
Hi Alastair,

For problems like this, let the unknown quantity be "x". Here, x represents the number of hours spent watching TV on Monday, Tuesday, Wednesday or Thursday.

Let y represents the number of hours spent watching TV on a Friday, Saturday or Sunday. We are told that he watches twice as much on these days. So, y=2x....[Fact #1]

Over a week, he watches T=4*x+3*y number of hours of TV.
The multipliers "4" (for MTWT) and "3" (for FSS) correspond to the number of days in each category.

Using [#1], T=4*x+3*(2x)=10x.
We are told that 24 hours are spent watching TV each week.
Setting this equal to T, we have 24=10x
x=24/10=2.4 hours.

Now, there are 60 minutes in an hour.
10% of this is equivalent to 0.1 hour or 6 minutes.
So, 0.4 hour = 4*6=24 minutes.

So, you can express the answer as 2 hours and 24 minutes.

Cheers.