Word problem help!?

Question

Grandmother’s Birthday

‘How old is your son?’ asked a man to his neighbor. ‘My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.
How old is the man’s son?

Answer 1

5.

That the mother is 5 times as old as her son, who is in turn 5 times the age of the daughter, menas the mothe's age has to be a multiple of 25, so she can be 25, 50 or 75.
However, the fact the husbad is twice as old as the wife would make him 50, 100 or 150, and being 100 or more would bust the requirement that the combined age is 81.

So, daughter is 1, son is 5, mother is 25, father is 50.
Total 81.

Answer 2

5

Answer 3

OK, the others have given you the right answer, but they have not explained HOW. Let x equal the daughter's age.
Daughter= x = 1x
Son = 5 * Daughter = 5 * 1x = 5x
Wife=5 * Son = 5 * 5x = 25x
Me=2 * Wife = 2 * 25x = 50x
Grandma = Daughter + Son + Wife + Me = 81
Grandma = 1x + 5x + 25x + 50x
81 = 81x
1 = x

So:
Daughter is 1
Son is 5
Mom is 25
I am 50
Grandma is 81!!!

I laid out the entire problem so you could (hopefully) see my work.

Answer 4

D = daughter, S = son, W = wife, H = husbund
S=5D W=5S (or you could say W= 5*5D) H=2W (or you could say H=2*5*5D) You know that everyone added together equals the Grandmother or 81.
D + 5D + 5*5D + 2*5*5D = 81
Use x for the daughter and you get:
x + 5x + 5(5x) + 2(5(5x)) = 81
81x = 81
x = 1, son = 5x or 5

Answer 5

Son is 5 - daughter is 1...wife is 25.....you are 50 = granmother 81

Answer 6

x + x/5 + 5x + 2*5x = 81
x(1 + 1/5 + 5 + 10) = 81
x(16 + 1/5) = 81
x(80 + 1)/5 = 81
x = 5*81/81 = 5