Answer:
C. 40
Step-by-step explanation:
Let us say there are x 7's and y 77's.
We have been given that each term in the sum a1+a2+a3+...+an is either 7 or 77 and the sum equals 350. We are asked to find the value of n.
Since the sum of all numbers is 350, so we can represent this information in an equation as:

The only integer solutions for the equation
are 10, 20, 30, 40, 50
.
So, there can be these many terms: 10 or 20 or 30 or 40 or 50
.
The given option only contains 40, so 40 would be the answer. For 40 terms to be there, there has to be 39 sevens and 1 seventy-seven.
Let us verify our answer.




Therefore, the total terms (n) could be equal to 40 and option C is the correct choice.
Answer:
The probability is 0.31
Step-by-step explanation:
To find the probability, we will consider the following approach. Given a particular outcome, and considering that each outcome is equally likely, we can calculate the probability by simply counting the number of ways we get the desired outcome and divide it by the total number of outcomes.
In this case, the event of interest is choosing 3 laser printers and 3 inkjets. At first, we have a total of 25 printers and we will be choosing 6 printers at random. The total number of ways in which we can choose 6 elements out of 25 is
, where
. We have that 
Now, we will calculate the number of ways to which we obtain the desired event. We will be choosing 3 laser printers and 3 inkjets. So the total number of ways this can happen is the multiplication of the number of ways we can choose 3 printers out of 10 (for the laser printers) times the number of ways of choosing 3 printers out of 15 (for the inkjets). So, in this case, the event can be obtained in 
So the probability of having 3 laser printers and 3 inkjets is given by

Answer:
0.278
Step-by-step explanation:
Given that Nuri joins a game for a car. The rule is that Nuri pick one key from box either A, B, or C. A box has two keys but only one can be used. B box has three keys but only one can be used. C box has two keys but none of them can be used.
Each box is equally likely to be selected.
In other words

If A is selected then probability of winning is using the correct key out of two keys i.e. 0.5
If B is selected then probability of winning is using the correct key out of three keys i.e. 0.333
If c is selected then probability of winning is using the correct key out of two keys i.e. 0.00
So the probability that Nuri can win the car
= 
Answer :
The shape of the distribution of the sample usually contains the given two points :
1. The sampling distribution is skewed for small sample sizes. Also, the distribution will be non-normal if the sample size is small
2. The shape of the sampling distribution gets more and more normal-like (bell shaped) as the sample size increases
For sample size, n = 2
The sampling distribution will be skewed for this sample size
For sample size, n = 70
The shape of the sampling distribution for sample size of 70 will be more normal as compared to that of sample size of 2