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 
Answer:5/2a + 10/3b
Step-by-step explanation:
(1/6)(15a+20b)
=(1/6)(15a)+(1/6)(20b)
Answer: 6.2
Step-by-step explanation: 3.1 = x/2
x/2=3.1
x/2(2)=3.1(2)
x=6.2
Answer:
4 Hours
Step-by-step explanation:
Let's say that the rate of the machines 1/x, because every time they complete an order, it takes them x hours. To find x, we have to add the the rates of the individual machines, which would equal the rate of the machines working together. We know that there are four machines working together at the same rate, and it took them 32 hours.
So:
1/x + 1/x + 1/x + 1/x = 1/32
1/4x = 1/32
4x = 32
x = 8
Thus, the rate of the machines is 1/8.
Now we have to find the time of the order with only half of the machines working together. This time, we don't know the combined rate, so I'll substitute it for y.
1/8 + 1/8 = 1/y
1/4 = 1/y
y = 4
The time taken to complete it is 4 hours.