3+4=7
7 x 8=56
There will be 56 airplanes :)Hope this helped!
Answer:
There is a 24.3% probability that one of the calculators will be defective.
Step-by-step explanation:
For each calculator, there are only two possible outcomes. Either it is defective, or it is not. So we use the binomial probability distribution to solve this problem.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
The probability of a defective calculator is 10 percent.
This means that 
If 3 calculators are selected at random, what is the probability that one of the calculators will be defective
This is P(X = 1) when n = 3. So


There is a 24.3% probability that one of the calculators will be defective.
Answer:
The first choice is the answer of course
Answer:
Step-by-step explanation:
The total height of the can is 20cm
Sample space is 36C4
Now, we want to know all of the combinations that have 1 digit in it.
So, we can have one here:
1XXX
X1XX
XX1X
XXX1
But we have 10 different digits to choose from. So, we need to introduce the combination term, nCr, where n is a list of all digits and r is how many we want.
Since we only want one, we will need 10C1 for the number of digits. But we need to choose three lowercases, so it becomes 10C1 × 26C3
Since it's a probability question, we need to divide that by our sample space, 36C4, and our percentage becomes 44%