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

To solve this problem, we need to use the formula for the average, which is the sum of the numbers divided by the quantity of numbers.

1. The average of 6 numbers is 60. So, the sum of these 6 numbers is 60 * 6 = 360.

2. The average of the first four numbers is 50. So, the sum of these 4 numbers is 50 * 4 = 200.

3. The average of the last three numbers is 70. So, the sum of these 3 numbers is 70 * 3 = 210.

4. Now, we know that the fourth number is included in both the first four numbers and the last three numbers. So, to find the fourth number, we subtract the sum of the first four numbers and the sum of the last three numbers from the total sum of the six numbers.

   The fourth number is 360 - 200 - 210 = -50.

However, a number cannot be negative in this context, so there seems to be a mistake in the problem. The sum of the first four numbers and the last three numbers should be equal to the sum of all six numbers, but in this case, it is greater. Therefore, none of the provided options are correct.