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.
Praveen said:
3 years ago
Present ages sum 56 right soo to go through options we have to find the sum of ages eight years ago.
There are persons soo each got eight year's ago age ---> 8*3=24.
Eight years ago sum=present sum+three members sum of eight years ago age.
The sum of ages at right years ago = 56+24=80 and check with the option that should be got the sum of three ages will be 80.
There are persons soo each got eight year's ago age ---> 8*3=24.
Eight years ago sum=present sum+three members sum of eight years ago age.
The sum of ages at right years ago = 56+24=80 and check with the option that should be got the sum of three ages will be 80.
(3)
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
Jon said:
8 years ago
I didn't understand.
First of all, from where 80 came.
Secondly, how do we know that we must plus, 4x-8 and 7x-8 how come there is + in between. Isn't it 8 years ago. Then why plus?
Please, someone, explain in very simple manner.
First of all, from where 80 came.
Secondly, how do we know that we must plus, 4x-8 and 7x-8 how come there is + in between. Isn't it 8 years ago. Then why plus?
Please, someone, explain in very simple manner.
Ronak said:
1 decade ago
The total of ratios is 20 (4+7+9).
The total of ages will become 56 + (8x3) = 56+24 = 80.
Now 20 x 4 = 80,
So the multiple is 4. So the common multiple is 4 for all.
Now we get present ages of all.
4x4 = 16.
7x4 = 28.
9x4 = 36.
The total of ages will become 56 + (8x3) = 56+24 = 80.
Now 20 x 4 = 80,
So the multiple is 4. So the common multiple is 4 for all.
Now we get present ages of all.
4x4 = 16.
7x4 = 28.
9x4 = 36.
Tirth Patel said:
7 years ago
4 + 7 + 9 = 20x.
Eight years ago* three persons(8*3)=24.
Sum of their ages was= 56.
24+56=80x.
80/20=4.
Then 4:7:9 multiply by 4.
(4*4)=16,
(7*4)=28,
(9*4)=36.
The Answer is 16, 28, 36.
Eight years ago* three persons(8*3)=24.
Sum of their ages was= 56.
24+56=80x.
80/20=4.
Then 4:7:9 multiply by 4.
(4*4)=16,
(7*4)=28,
(9*4)=36.
The Answer is 16, 28, 36.
(4)
Yunus said:
10 years ago
It is simple that eight years ago 56 and now 3 persons*8 years each = 24 years.
So 56+24 = 80 now we check options the sum of 80 is 16+28+36 = 80 is option B answer.
So 56+24 = 80 now we check options the sum of 80 is 16+28+36 = 80 is option B answer.
Lavanya said:
9 years ago
8 years ago sum of their age is 56,
Present sum of their age is 80
Total parts of the ratio is 4+7+9 = 20
So, 80/20=4
4 * 4 ,7 * 4, 9 * 4 = 16, 28, 36.
Present sum of their age is 80
Total parts of the ratio is 4+7+9 = 20
So, 80/20=4
4 * 4 ,7 * 4, 9 * 4 = 16, 28, 36.
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.
Ramya said:
9 years ago
It is simple method.
He has given present ages of persons mentioned that 8 years ago, then we can take as;
(4x - 8) + (7x - 8) + (9x - 8) = 56.
He has given present ages of persons mentioned that 8 years ago, then we can take as;
(4x - 8) + (7x - 8) + (9x - 8) = 56.
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 !!!! :)
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