Average of 8 numbers is 40. The average of first three numbers is 46 a...
Sum of the 8 numbers = 8 × 40 = 320
Sum of first 3 numbers = 3 × 46 = 138
Sum of next two numbers = 2 × 50 = 100
Let the 6th number be ‘x
⇒ 7th number = x + 6
⇒ 8th number = x + 10
Hence,
⇒ 138 + 100 + x + x + 6 + x + 10 = 320
⇒ 3x = 320 – 254
⇒ x = 66/3 = 22
∴ The 8th number = 22 + 10 = 32
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Average of 8 numbers is 40. The average of first three numbers is 46 a...
Given information:
- The average of 8 numbers is 40.
- The average of the first three numbers is 46.
- The average of the next two numbers is 50.
- The sixth number is 6 less than the seventh number.
- The sixth number is also 10 less than the eighth number.
Let's solve this step by step:
1. Average of 8 numbers is 40:
We can find the sum of the 8 numbers by multiplying the average by the total number of numbers. So, the sum of the 8 numbers is 8 * 40 = 320.
2. Average of the first three numbers is 46:
The sum of the first three numbers can be found by multiplying the average by the number of numbers. So, the sum of the first three numbers is 3 * 46 = 138.
3. Average of the next two numbers is 50:
The sum of the next two numbers can be found in a similar way. So, the sum of the next two numbers is 2 * 50 = 100.
4. The sixth number is 6 less than the seventh number:
Let's assume the seventh number is 'x'. Then, the sixth number will be 'x - 6'.
5. The sixth number is also 10 less than the eighth number:
Let's assume the eighth number is 'y'. Then, the sixth number will be 'y - 10'.
6. Equating the sum of the first three numbers, next two numbers, and the sixth number with the given sum:
138 + 100 + (x - 6) + (y - 10) = 320
7. Simplifying the equation:
238 + x + y - 16 = 320
x + y + 222 = 320
x + y = 320 - 222
x + y = 98
8. Solving the equation for 'x' and 'y':
From the equation x + y = 98, we can see that the values of x and y should add up to 98. Since we don't have any information about the exact values of x and y, there can be multiple solutions. However, we can find the value of y by assuming a value for x.
Let's assume x = 40. Then, y = 98 - 40 = 58.
Therefore, the value of the eighth number (y) is 58, which corresponds to option 'D'.