Question

mean of 6 numbers is is 50. the mean of last four numbers is 40 and first three is 70. then the four the number is​

Answer 1

Answer:

1

1

The average of 7 numbers is 50. The average of the first three is 40, while the average of the last three is 60. What must be the remaining number?

3D Borderless sense screen.

C. S. Sharma

Answered April 1, 2019

Imagine that seven numbers are a, b, c, d, e, f and g . The average of these 7 numbers is 50. As such

Sum of these numbers will be

a+b+c+d+e+f+g

Average = sum of the numbers/ n

Accordingly (a+b+c+d+e+f+g)/7=50

(a+b+c+d+e+f+g)=50×7

(a+b+c+d+e+f+g)=350…Eq.1

As per the statement, the average of first three numbers is 40, means

(a+b+c)/3=40

(a+b+c)=40×3

(a+b+c)=120…Eq. 2

Further, the statement suggest the average of last three numbers is 60

(e+f+g)/3=60

(e+f+g)=60×3

(e+f+g)=180…Eq.3

Substitute the value of (a+b+c) from Eq. 2 and the value of (e+f+g) from Eq. 3 into the Eq. 1

(a+b+c+d+e+f+g)=350…Eq.1

(a+b+c)+d+(e+f+g)=350

120+d+180=350

d+300=350

d=350–300

d=50

Thus the value of remaining number d is 50

Answer the value of remaining number is 50