Answer:
y - x = - 2 b
Step-by-step explanation:
Given-
3 x + 2 y = 5 a + b...................(i)
4 x - 3 y = a + 7 b.....................(ii)
<em><u>Multiply by 3 and 2 in equation (i) & (ii) respectively-</u></em>
<em><u>Add equation (iii) & (iv)-</u></em>
9 x + 6 y = 15 a + 3 a...................(iii)
<u>8 x - 6 y = 2 a + 14 b</u> ...................(iv)
17 x = 17 a + 17 b
<u>x = a + b</u>
Put x = a + b in equation (i)-
<em>2 y = 5 a + b - 3 a - 3 b</em>
<em>2 y = 2 a - 2 b</em>
<u>y = a - b </u>
<em>∴ y - x = a - b - ( a + b )</em>
<em>y - x = a - b - a - b</em>
y - x = - 2 b
The price for each instructor will be the same at 3 hours. How I determined this answer:
First off, you need to add the initial price and hourly price for each person together, so you already know how much it will cost for 1 hour, including the initial fee. Here's how you do it:
Ieda: $11.00 (hourly price) + $8.50 (initial fee) = $19.50 (for 1 hour)
Thanh: $10.50 (hourly price) + $10.00 (initial fee) = $20.50 (for 1 hour)
Now that you have the price for 1 hour including the initial fee, now you need to find the price for each hour after that. Here's how I did that:
I created a graph that looked like this:
Hours: 1 2 3
Ieda: 19.50 30.50 41.50
Thanh: 20.50 31.00 41.50
Here's how I figured out the price for each hour:
Ieda:
Hour 1 (including initial price):
$11.00 + $8.50 = $19.50
Hour 2 (excluding initial price): Only add the hourly price after Hour 1!
$19.50 + $11.00 = $30.50
Hour 3 (excluding initial price):
$30.50 + $11.00 = $41.50
Thanh:
Hour 1 (including initial price):
$10.50 + $10.00 = $20.50
Hour 2 (excluding initial price):
$20.50 + $10.50 = $31.00
Hour 3 (excluding initial price):
$31.00 + $10.50 = $41.50
So, looking at the graph, their prices are the same once each instruction reaches 3 hours. ($41.50)
I hope I was able to help you! :)
Answer:
.065
Step-by-step explanation:
The total number of marbles is
4 blue marbles+ 6 red marbles+ 3 yellow marbles+5 black marbles=18
P(1st black) = Black/total = 5/18
You keep the marble
The total number of marbles is
4 blue marbles+ 6 red marbles+ 3 yellow marbles+4 black marbles=17
P(2st black) = Black/total = 4/17
Multiply the probabilities together
P(black,black)= 5/18 * 4/17 =10/153=.065359477 =.065
Answer:
9
Step-by-step explanation:
