1. ## Linear Equations +fullrep

Find the value of k that makes the following function continuous. Justify your answer.

f(x) = { x +3 if x < 1
-2x + k if x >/= 1

Graham's long-distance telephone plan includes the first 500 minutes per month in the \$15.00 charge. For each minute after 500 minutes, Graham is charged \$0.02. Write a function that describes Graham's total long-distance charge in terms of the number of long distance minutes he uses in a month.

+FULLrep for a process + explanation please =( Fuk dis shiz

2. Originally Posted by Mint
At 9:20 am, Adrian left Windsor with 64L of gas in his car. He drove east at 100 km/h. The low fuel warning light came on when 10 L of gas were left. Adrian's car uses gas at the rate of 8.8L/100km. When did the warning light come on?

+FULL(5)rep for a detained explanation as to how you get your answer, which should be 6h 8m after 9:20 am (3:28 pm) Help wanted pleaseeeeeeee >_<
Okay so Adrian started with 64 L in his gas tank and the light came on when he had 10 L left, so he used 54 L in that time. If he is going 100 km/h, he uses 8.8 L every 100 km he travels. So you need to divide 54 by 8.8 and you get 6.13, or 6 hours and .13 of an hour (which just happens to be 8 minutes) If he left at 9:20, you add the 6 hours and 13 minutes to the time until you get your answer of 3:28 PM

As for #2, that' a bit more tricky. You should first start with the total amount in each category (25k, 35k etc) and choose the highest number in that range. So in this case, lets use 35k. Now if she sells 35k worth of stuff, she gets 5.5% sales. Now you multiply 35000 by .055 to get her commission of \$1925. You should do this for all of them (25k * .05, 35k * .055, 45k * .06, and 50k * .07) Now that you've found all those numbers, look for the range where \$2000 would fall in (the 6% on 35k-45k) Now that you know the percent, you divide 2000 by .06 to get your answer

Edit: Actually #2 doesnt quite equal 38333, it only equals \$33333 so blah

3. Originally Posted by Andymac106
Okay so Adrian started with 64 L in his gas tank and the light came on when he had 10 L left, so he used 54 L in that time. If he is going 100 km/h, he uses 8.8 L every 100 km he travels. So you need to divide 54 by 8.8 and you get 6.13, or 6 hours and .13 of an hour (which just happens to be 8 minutes) If he left at 9:20, you add the 6 hours and 13 minutes to the time until you get your answer of 3:28 PM
Originally Posted by Andymac106
Okay so Adrian started with 64 L in his gas tank and the light came on when he had 10 L left, so he used 54 L in that time. If he is going 100 km/h, he uses 8.8 L every 100 km he travels. So you need to divide 54 by 8.8 and you get 6.13, or 6 hours and .13 of an hour (which just happens to be 8 minutes) If he left at 9:20, you add the 6 hours and 13 minutes to the time until you get your answer of 3:28 PM
The textbook process says something a LOT more complicated =___=

G=64-8.8t,
where G = amount of gas (L) and t = time (hours)

10 = 64 - 8.8t
10 - 10 = 64 - 8.8t - 10
0 = 54 - 8.8t
8.8t = 54
t = 54/8.8
t = 6.14

0.14 x 60 = 8.4

The warning light came on about 6h 8m after 9:20 am, which is about 3:28 pm

------------

Could you explain this process to me? I dont really get it, your explanation makes more sense, but I have a feeling the above process is really important D:
Like, if G is the amount of gas in litres, why is it 10 and not 64???

4. Originally Posted by Mint
The textbook process says something a LOT more complicated =___=

G=64-8.8t,
where G = amount of gas (L) and t = time (hours)

10 = 64 - 8.8t
10 - 10 = 64 - 8.8t - 10
0 = 54 - 8.8t
8.8t = 54
t = 54/8.8
t = 6.14

0.14 x 60 = 8.4

The warning light came on about 6h 8m after 9:20 am, which is about 3:28 pm

------------

Could you explain this process to me? I dont really get it, your explanation makes more sense, but I have a feeling the above process is really important D:
Like, if G is the amount of gas in litres, why is it 10 and not 64???
What your text book said is exactly what I said, just put in a prettier equation

G is 10 because that's how much gas there was when the light came on. You're looking for when the light came on now when you originally started. So you have 10 = 64-8.8t which is showing that (64-8.8t) must equal 10. Now the next step is to subtract 10, which IMO, is useless. Because you are trying to isolate your variable so why not just subtract 64 from the right side?? But the key is to end up with 54 = 8.8t (or if you used my method, -54 = -8.8t, whichever way you decide to isolate the variable) now you must divide everything by 8.8. (or -8.8 but I'm sure you're keeping up with that ) You end up with t = 6.14. The 6 represents the whole number of hours. You multiply .14 by 60 to get 8.4 to find the number of minutes. Did that help?

5. ## The Following User Says Thank You to Andymac106 For This Useful Post:

Mint (02-06-2014)

6. Updated with new problems sigh

7. f(x) = {im gonna kms

8. ## The Following User Says Thank You to Mint For This Useful Post:

Raj (02-08-2014)

9. Are those 2 up there separate problems or just 1 problem?

10. Originally Posted by Andymac106
Are those 2 up there separate problems or just 1 problem?

I hated this in high school.

I DID MY TIME, TWELVE YEARS OF IT. IN AZKABAN.

12. Originally Posted by Mint
Find the value of k that makes the following function continuous. Justify your answer.

f(x) = { x +3 if x < 1
-2x + k if x >/= 1

Graham's long-distance telephone plan includes the first 500 minutes per month in the \$15.00 charge. For each minute after 500 minutes, Graham is charged \$0.02. Write a function that describes Graham's total long-distance charge in terms of the number of long distance minutes he uses in a month.

+FULLrep for a process + explanation please =( Fuk dis shiz
#2, since it looks easier So you have a constant value of \$15 every month. Then you have .02x when x > 500 where x is the number of minutes that he talks. Now I believe that you would write it like this: C (cost) = .02x + 15 if x > 500. C = 15 if x < 500. Does that make sense? Now I'm pretty positive thats how you write it, just not 100% like I have been on all the rest that I've helped you with..