The average of six numbers is 30. If the average of first four is 25 and that of last three is 35, the fourth number is:
Question
The average of six numbers is 30. If the average of first four is 25 and that of last three is 35, the fourth number is:
Solution
Sure, let's solve this step by step:
-
The average of six numbers is 30. Therefore, the sum of these six numbers is 30 * 6 = 180.
-
The average of the first four numbers is 25. Therefore, the sum of these four numbers is 25 * 4 = 100.
-
The average of the last three numbers is 35. Therefore, the sum of these three numbers is 35 * 3 = 105.
-
Notice that the fourth number is counted in both the first four numbers and the last three numbers.
-
If we add the sum of the first four numbers (100) and the sum of the last three numbers (105), we get 205. But we know that the sum of all six numbers is 180.
-
Therefore, the fourth number, which was counted twice, is 205 - 180 = 25.
Similar Questions
The average of six numbers is 48. If the average of first four is 28 and that of last three is 41, the fourth number is: Options :475149none of these
The average of 6 numbers is 60. If the average of first four is 50 and that of last three is 70, the fourth number isOptions353050None of these
The average of 9 numbers is 30.If the average of first '5' numbers is 25 and that of the last '3' number is 35.Then the 6th number?30405060
There are 4 numbers. If we leave the first number, the average of the remaining becomes 30. If we leave the second number, the average of the remaining becomes 25, while, if we leave the third number, the average of the remaining becomes 50. If we leave the fourth number, the sum of the remaining becomes 135. Find the average of the 4 numbers?
There are 4 natural numbers. If average of any 3 numbers is added with the fourth, 28, 21,18 or 25 will be obtained. Find the average of the original 4 numbers
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.