<em>*To solve for a specified variable, you need to isolate that variable onto one side.</em>
<h3>11.</h3>
Firstly, subtract 5r on both sides: 
Lastly, divide both sides by 2 and <u>your answer will be
</u>
<h3>12.</h3>
First, subtract z on both sides of the equation: 
Next, divide both sides by y and <u>your answer will be
</u>
<h3>13.</h3>
Firstly, multiply both sides by b: 
Next, divide both sides by c and <u>your answer will be
</u>
Answer:

Step-by-step explanation:
So we know that:

To reflect across the <em>y-axis</em>, instead of x, use -x. Therefore:

Simplify:

And that's our answer :)
a) means what is the probability of P occurring once Q has occurred. That is 9/24 which is 3/8.
b) is 14/24 which is 7/12.
Please inform me if I gave you the correct answers :)
Answer:
The minimum number of letters John has to send to be sure that Peter receives his letter is 127 letters
Step-by-step explanation:
The four digit numbers that are multiples of 5 and 7 with the last digit = 0 is found as follows
Since the last digit of the house number = 10, then the house number is divisible by 10 which also meets the condition that the house number is divisible by 5
We have the four digit numbers from 1000 to 9999
Hence the numbers divisible by both 7 and 10 are from (1000/70 (Which is 14 + 2/7) - 2/7)×70 + 70 = 1050 to (9999/70 (Which is 142 + 59/70)- 59/70)×70= 9940
Which gives 142 - 15 = 127 numbers which are four digit number multiples of 5 and 7 with the last digit = 0
Hence the minimum number of letters John has to send to be sure that Peter receives his letter = 127 letters.