Q-Five years ago,ram was three times as old as shyaam,four years from now,ram will be only twice as old as shyaam.what is the present age of ram
a-30
b-32
c-36
d-40
Answers
• Let present age of Ram be "M" years and present age of Shyam be "N" years.
Five years ago,
Age of Ram = (M - 5) years
Age of Shyam = (N - 5) years
》 Five years ago, Ram was three times as old as Shyam
According to question,
=> M - 5 = 3(N - 5)
=> M - 5 = 3N - 15
=> M = 3N - 15 + 5
=> M = 3N - 10 ________ (eq 1)
Fours years from now,
Age of Ram = (M + 4) years
Age of Shyam = (N + 4) years
》 Four years from now, Ram will be twice as old as Shyaam.
According to question,
=> (M + 4) = 2(N + 4)
=> M + 4 = 2N + 8
=> M = 2N + 4
=> 3N - 10 = 2N + 4 [From (eq 1)]
=> 3N - 2N = 4 + 10
=> N = 14
[ Present age of Shyaam ]
Put value of N in (eq 1)
=> M = 3(14) - 10
=> M = 42 - 10
=> M = 32
[ Present age of Ram ]
So,
Present age of Ram = 32 years
option b) 32
Given :-
- Five years ago,Ram was three times as old as Shyaam
- Four years from now,Ram will be only twice as old as Shyaam
To find :-
- Present age of Ram
Solution :-
Let the present age of Ram be x years
Let the present age of Shyaam be y years
As per the first condition,
- Five years ago,Ram was three times as old as Shyaam
Five years ago,
Age of Ram = x - 5
Age of Shyaam = y - 5
Now let's form our first equation using the given condition,
x - 5 = 3 ( y - 5 )
x - 5 = 3y - 15
x - 3y = - 15 + 5
x - 3y = - 10 ------> 1
As per the second condition,
- Four years from now,Ram will be only twice as old as Shyaam.
Four years from now,
Age of Ram = x + 4
Age of Shyaam = y + 4
Let's form our second equation representing the condition mathematically,
x + 4 = 2 ( y + 4 )
x + 4 = 2y + 8
x - 2y = 8 - 4
x - 2y = 4 -----> 2
We have our two equations. Solve them via elimination method, simultaneously.
Subtract equation 2 from 1,
..+ x - 3y = - 10 -->1
( + x - 2y = + 4 )----> 2
__________________
- y = - 14
[Cancelling minus from both sides]
y = 14
Present age of Shyaam = y = 14 years
Substitute, y = 14, in equation 1,
x - 3y = - 10 -----> 1
x - 3 ( 14) = - 10
x - 42 = - 10
x = - 10 + 42
x = 32
Present age of Ram = x = 32 years
For first case :-
- Five years ago,Ram was three times as old as Shyaam
Five years ago,
Ram's age = 32 - 5 = 27
Shyaam's age = 14 - 5 = 9
Ram's was three times as old as Shyaam, so let's check if the condition satisfies.
27 = 3 (9)
27 = 27
LHS = RHS.
For second case :-
- Four years from now,Ram will be only twice as old as Shyaam
Four years from now,
Ram's age = 32 + 4 = 36 years
Shyaam's age = 14 + 4 = 18 years
Ram will be only twice as old as Shyaam, so let's check whether this condition is satisfied or not.
36 = 2 ( 18)
36 = 36
LHS = RHS.
Hence our answer is right.