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# If The average of 13 numbers is 68 that of the first 7 is 63 and of the last 7 is 70 what is the 7th number?

Updated: 9/18/2023

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Q: If The average of 13 numbers is 68 that of the first 7 is 63 and of the last 7 is 70 what is the 7th number?
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### What is the quickest way to add the first 25 odd numbers?

Use the formula for an arithmetic series. That is, take the average of the first and the last number in the series, and multiply by 25. The first number in the series of course is 1; the last number is 1 + 2(24), since there are 24 intervals.

### What is the average of the first ten odd numbers?

Just add them together, and divide the result by 10. (For the average of a larger set of consecutive odd numbers, it's faster to use the formula for an arithmetic series to add them up. Also, the average of such a set is the same as if you just average the first and the last number.)

31.

### What is the average of seven numbers if the average of the first two is 9 and the average of the last five is 16?

first two add up to 2 x 9 = 18 last 5 add up to 5 x 16 = 80 total of all numbers = 98 Average of all seven numbers = 14

### How is the last digit of a measurement different from the other digits?

the first number is usually in feet, the last number is in inches. so the last number = 1/12 of the first numbers value.

12

### What are the first 10 numbers in pie?

The first ten numbers in pie are : 3.141592654 (the last 4 is from rounding it from the number below) The sixteen numbers of pie are: 3.141592653589793

### Can you define mode?

The Mode is another word for the Average. This means that it is the number that is most likely to occur if you repeat the action that gave you the last numbers. To get the mode, it is pretty simple. You first add all the numbers together, and divide them by the amount of numbers you had to begin with.

### How do you find the median in an odd number of data?

List the numbers in order, cross out the first number, the last number, the second first number then the second last number, and so on. The only number left is your median.Here's an Example:Here's the set of numbers.3,9,5,6,1,2,8Place them in order.1,2,3,5,6,8,9Crossing out.1,2,3,5,6,8,91,2,3,5,6,8,91,2,3,5,6,8,9Your answer is revealed!Your final answer is 5.

### How do you calculate the sum of all numbers from 1 through 100?

The formula for the sum of an arithmetic sequence is ((first number) + (last number)) x (how many numbers) / 2, in this case, (1 + 100) x 100 / 2.The formula for the sum of an arithmetic sequence is ((first number) + (last number)) x (how many numbers) / 2, in this case, (1 + 100) x 100 / 2.The formula for the sum of an arithmetic sequence is ((first number) + (last number)) x (how many numbers) / 2, in this case, (1 + 100) x 100 / 2.The formula for the sum of an arithmetic sequence is ((first number) + (last number)) x (how many numbers) / 2, in this case, (1 + 100) x 100 / 2.

### Find the sum of the first 500 counting numbers?

I think you asking what is 1 + 2 + .. 499 + 500. There is a simple way to compute such sums-- Find the average of the numbers and multiply by the number of items in the list. Further the average is just the sum of the first plus the last number in the list, since all of the numbers differs by the same amount. So, the average is (1+500)/2 and there are 500 number is the list, so the sum is (501/2)* 500 = 250*501. [I use * to mean multiply.}