Each number in the code can be 1 of 10 numbers.
The total number of possible combinations is 10 * 10 * 10 * 10 = 10,000
The probability of getting 1234 would be 1/10,000
R = v/4
because:
v = 4r
v/4 = 4r/4 the fours cancel out and you are left with r
therefore v/4 = r or r = v/4
10 % = 24
20 % = 2 x 10%
20 % = 48
240 + 48 = 288
hope this helps you
Answer:

Step-by-step explanation:
In probability,
"AND" means "multiplication"
"OR" means "ADDITION"
We want probability of Blue Pen and Yellow Highlighter. So we find individual probabilities and "MULTIPLY" them.
Let P(b) be probability of blue pen
Let P(y) be probability of yellow highlighter
We know probability of event is that event divided by total number of that
So,
There are 4 + 2 = 6 pens
Blue pen = 2
Hence,
P(b) = 2/6 = 1/3
And,
There are 5 highlighters
Yellow highlighter = 1
Hence,
P(y) = 1/5
Now,
P(b and y) = 1/3 * 1/5 = 1/15
Hence,
probability of grabbing blue pen and a yellow highlighter is 