Question

Q8. The average of 7 numbers is 60. The average of the first three numbers is 50, while the average of the last three is 70. What must be the remaining number?

Answer 1

Sum of the 7 numbers:

Average = 60

Sum = 60 x 7 = 420

Sum of the first 3 numbers:

Average = 50

Sum = 50 x 3 = 150

Sum of the last 3 numbers:

Average = 70

Sum = 70 x 3 = 210

Sum of the 6 numbers:

Sum = 150 + 210 = 360

Find the remaining number:

Remaining number = 420 - 360 = 60

Answer: The number is 60

Answer 2

average of 7 number=60
total of 7 numbers=60×7=420
average of 1st three numbers=50
sum of 1st three number=50×3=150
average of last three numbers=70
sum of last three numbers=70×3=210
total sum=420
150+210+remaining number=420
remaining number=420-150-210=60