Question

Next door to me live four brothers of different heights.Their average height is 74 inches, and the difference in height among the first three men is two inches. The difference between the third and the fourth man is six inches.
Can you tell how tall is each brother?

Answer 1

Age of 4 Brothers are as follow:
1st - 70 Inches
2nd - 72 inches
3rd - 74 inches
4th - 80 inches

Let 1st be a, 2nd be b, 3rd be c & 4th be d
a = a
b = a+2
c = b+2 = a+2+2
d = c+6 = a+2+2+6

Thus,
74=(a+b+c+d)/4
74=(a+a+2+a+2+2+a+2+2+6)/4
74=(4a+16)/4
74=a+4
a=70.
Thus,
b = a+2 = 70+2 = 72
c = a+2+2 = 70+2+2 = 74
d = a+2+2+6 = 70+2+2+6 = 80.

Comments

Why it should be x+2 and NOT x-2 and so on?

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Why it should be x+2 and x-2 and so on?

Answer 2

Let X= height of first brother
Let Y= height of second brother
Let Z= height of third brother
Let W= height of fourth brother
Then, Y = X - 2, Z = X - 4, W = X - 4 - 6
Average height
( X + ( X - 2) + ( X - 4) + ( X - 10) ) / 4 = 74
4 X - 16 = 296 , X = 78
Height of first brother : 78 inches
Height of second brother : 76 inches
Height of third brother : 74 inches
Height of fourth brother : 68 inches