Aptitude - Problems on Ages - Discussion
Discussion Forum : Problems on Ages - General Questions (Q.No. 11)
11.
The present ages of three persons in proportions 4 : 7 : 9. Eight years ago, the sum of their ages was 56. Find their present ages (in years).
Answer: Option
Explanation:
Let their present ages be 4x, 7x and 9x years respectively.
Then, (4x - 8) + (7x - 8) + (9x - 8) = 56
20x = 80
x = 4.
Their present ages are 4x = 16 years, 7x = 28 years and 9x = 36 years respectively.
Discussion:
41 comments Page 1 of 5.
Neha said:
2 decades ago
How 20x comes?
Faruk said:
2 decades ago
4x+7x+9x = 56+8+8+8
20x = 80
is it simplified.
20x = 80
is it simplified.
Affrin said:
1 decade ago
(4x-8)+(7x-8)+(9x-8) = 56 --->(1)
Now add all the "x" values and "numerical number" separetely in eqn (1) then we get:
4x+7x+9x = 20x
(-8)+(-8)+(-8) = -24
20x-24 = 56
20x = 56+24
20x = 80
x = 80/20
x = 4
so,for calculating the current age we are substituting x=4 in (4x:7x:9x)= we get the ratio as 16:28:36
Now add all the "x" values and "numerical number" separetely in eqn (1) then we get:
4x+7x+9x = 20x
(-8)+(-8)+(-8) = -24
20x-24 = 56
20x = 56+24
20x = 80
x = 80/20
x = 4
so,for calculating the current age we are substituting x=4 in (4x:7x:9x)= we get the ratio as 16:28:36
Habib said:
1 decade ago
For such ques......jst simply look at the options !!!!
Try subtracting 8 frm B...and den add u get 56 !!!!
Hit and Trial...saves time !!!! :)
Try subtracting 8 frm B...and den add u get 56 !!!!
Hit and Trial...saves time !!!! :)
JAGADEESH said:
1 decade ago
4x+7x+9x=80
20x=80
x=4
then we get answer
20x=80
x=4
then we get answer
Rahima said:
1 decade ago
Just add all the x terms and numerical terms seperately.
Shiva said:
1 decade ago
Shiva
(4x-8)+(7x-8)+(9x-8)= 56
Remove the braces.
4x-8+7x-8+9x-8 =56
Now seperate variables and numeric terms.
4x+7x+9x=56+8+8+8
20x=80
x=4.
njoy.
(4x-8)+(7x-8)+(9x-8)= 56
Remove the braces.
4x-8+7x-8+9x-8 =56
Now seperate variables and numeric terms.
4x+7x+9x=56+8+8+8
20x=80
x=4.
njoy.
Payal said:
1 decade ago
Habib method was good
Ganesh said:
1 decade ago
Nice and easy method.
Pragathi said:
1 decade ago
Actually ago means past time so we have to add it's my doubt some times you will add some times you subtract please clarify it.
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