Question 940073
Q1) In 1921 Grandpa was twice as old as Tom was in 2000. In 1930 Grandpa was three times as old as Tom was in 2000. How old was Grandpa in 2000?

let tom age was in 2000 = x year
In 1921 Grandpa was twice as old as Tom was in 2000. 
in 1921 Grandpa age was = 2x year
in 2000 grandpa age was = 2x+79   (because 2000- 1921= 79 means after 79 years)---(1)
In 1930 Grandpa was three times as old as Tom was in 2000.
in 1930 Grandpa age was = 3x year
in 2000 grandpa age was = 3x+70   (because 2000- 1930= 70 means after 70 years)---(2)
from (1) and (2) we can relate
in 2000 grandpa age was=3x+70= 2x+79
⇒3x-2x=79-70
⇒x=9
Tom age was in 2000 = 09 years



Q2) In 1936 Grandma was twice as old as Sally was in 1999. In 1994 Grandma was three times as old as Sally was in 1999. How old was Grandma in 1999?

let sally age was in 1999 = y year
In 1936 Grandmaa was twice as old as sally was in 1999. 
in 1936 Grandmaa age was = 2y year
in 1999 grandmaa age was = 2y+63 (because 1999- 1936= 63 means after 63 years)---(3)
In 1994 Grandmaa was three times as old as sally was in 1999.
in 1994 Grandmaa age was = 3y year
in 1999 grandmaa age was = 3y+5  (because 1999- 1994= 05 means after 05 years)---(4)
from (3) and (4) we can relate
in 1999 grandmaa age was=3y+5= 2y+63
⇒3y-2y=63-05
⇒y=58
sally age was in 1999 = 58 years