Question Details

Three numbers are such that when the average of any two is added to the third, the results are 200, 180, and 160. What is the average of the three numbers?

Options

A

80

B

85

C

90

D

95

Show Answer

Correct Answer :

Option C

90

Solution :

The correct option is 90.

Let the three numbers be x, y, and z.

According to the problem, adding the average of any two numbers to the third gives the results 200, 180, and 160. We can formulate these into three equations:

x+y2+z=200

y+z2+x=180

+x2+y=160

To eliminate the fractions, multiply each equation by 2:

x+y+2z=400

2x+y+z=360

x+2y+z=320

Now, sum all three simplified equations together:

(x+y+2z)+(2x+y+z)+(x+2y+z)=400+360+320

Combine the like terms:

4x+4y+4z=1080

Factor out 4 from the left side of the equation:

4(x+y+z)=1080

Divide both sides by 4 to solve for the sum of the three numbers:

x+y+z=10804=270

The average of the three numbers is calculated by dividing their sum by 3:

Average=x+y+z3

Substitute the sum (270) into the average formula:

Average=2703=90

Hence, the average of the three numbers is 90.

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