00:01
He charges $30 service fee and $10 per hour.
00:05
And paul charges a $10 service fee and $15 an hour.
00:10
After how many hours will they both charge the same amount? so i'm going to subtract 15h from both sides.
00:21
So i have, and then i'm going to subtract 30 from both sides.
00:27
So negative 5h equals negative 20.
00:30
So h equals four.
00:34
So four hours, they will both be the same amount of money.
00:40
At a supply store, amelia bought three notebooks and five pens for $9 .50.
00:50
If a notebook costs 50 cents more than the pen, so notebook costs 50 cents more than the pen, how much does the notebook cost? so i'm going to plug this in for n and i'm going to say, okay, three times 0 .50 plus p plus 5p equals 9 .50.
01:21
So three times 0 .5 is 1 .5 plus 3 p plus 5 p plus 5 equals 9 .50.
01:35
1 .50 equals 8p plus 8p equals 9 .50.
01:43
Then i'm going to subtract 1 .50 from both sides.
01:49
And i have 8p equals 8.
01:52
Divide by 8 p equals 1.
01:56
So pens cost a dollar.
02:01
Okay.
02:03
And because pens costs a dollar, then notebooks cost.
02:09
A dollar 50 because they're 50 cents more than a pen a boat can maintain a constant speed of 34 miles per hour relative to the water the boat makes a trip upstream to a certain point in 21 minutes the return trip takes 13 minutes what is the speed of the current so constant the constant speed is 34 miles per hour okay the boat makes a trip upst stream, 21 minutes.
02:50
So 34 miles per hour in 21 minutes.
02:57
And the return trip takes 13 minutes.
03:04
Okay.
03:05
So 34 times 13 divided by 21.
03:14
So the speed of the current is 21 miles per hour...