Aptitude - Problems on Ages - Discussion
Discussion Forum : Problems on Ages - General Questions (Q.No. 7)
7.
Six years ago, the ratio of the ages of Kunal and Sagar was 6 : 5. Four years hence, the ratio of their ages will be 11 : 10. What is Sagar's age at present?
Answer: Option
Explanation:
Let the ages of Kunal and Sagar 6 years ago be 6x and 5x years respectively.
| Then, | (6x + 6) + 4 | = | 11 |
| (5x + 6) + 4 | 10 |
10(6x + 10) = 11(5x + 10)
5x = 10
x = 2.
Sagar's present age = (5x + 6) = 16 years.
Discussion:
128 comments Page 4 of 13.
Sahaya sahiln said:
1 decade ago
Step 1:
Let us consider kunal age is = x and sager age is = y.
Six years ago ages of kunal and sager is = 6:5.
So we can write x-6/y-6 = 6/5--->A.
Next, four years hence ages of kunal and sager is = 11:10.
So we can write x+4/y+4 = 11/10--->B.
Step-2:
Solve equation A and B, so.
Eqn A becomes,
X-6/y-6 = 6/5, so cross multiply becomes.
5x-30 = 6y-36->5x-6y+6 = 0.
5x-6y = -6-->C.
Eqn B becomes,
X+4/y+4 = 11/10, so cross multiply becomes.
10x+40 = 11y+44-->10x-11y-4 = 0.
10x-11y = 4-->D.
Solve eqn C and D.
5x-6y = -6->C.
10x-11y = 4->D.
2xeqn c, we get.
10x-12y = -12->E.
10x-11y = 4->D.
Step 3:
Eqn E (-) eqn D, so we can get.
10x-12y = -12.
-10+11y = -4.
So -y = -16.
We know (-) is cancel, so y = 16 = sager age.
Really I feel my explanation will under stand you.
Let us consider kunal age is = x and sager age is = y.
Six years ago ages of kunal and sager is = 6:5.
So we can write x-6/y-6 = 6/5--->A.
Next, four years hence ages of kunal and sager is = 11:10.
So we can write x+4/y+4 = 11/10--->B.
Step-2:
Solve equation A and B, so.
Eqn A becomes,
X-6/y-6 = 6/5, so cross multiply becomes.
5x-30 = 6y-36->5x-6y+6 = 0.
5x-6y = -6-->C.
Eqn B becomes,
X+4/y+4 = 11/10, so cross multiply becomes.
10x+40 = 11y+44-->10x-11y-4 = 0.
10x-11y = 4-->D.
Solve eqn C and D.
5x-6y = -6->C.
10x-11y = 4->D.
2xeqn c, we get.
10x-12y = -12->E.
10x-11y = 4->D.
Step 3:
Eqn E (-) eqn D, so we can get.
10x-12y = -12.
-10+11y = -4.
So -y = -16.
We know (-) is cancel, so y = 16 = sager age.
Really I feel my explanation will under stand you.
Jaspreet said:
1 decade ago
Lets sons age x and father y.
Then,
x+y = 60.
x-6 = 5(60-x) (put y=60-x).
6x = 306.
x = 306/6.
x = 51.
Son will be 60-51 = 9.
9+6 = 15 years hence.
Then,
x+y = 60.
x-6 = 5(60-x) (put y=60-x).
6x = 306.
x = 306/6.
x = 51.
Son will be 60-51 = 9.
9+6 = 15 years hence.
Pankaj said:
1 decade ago
Hi @Neha and @Faruk can you please explain what is "x" here?
Satyajeet said:
1 decade ago
The word ago means before. So, we should subtract.
Hence, the equation should be.
(6x-6)+4/(5x-6)+4 = 11/10.
Please, Explain me, if I am wrong.
Hence, the equation should be.
(6x-6)+4/(5x-6)+4 = 11/10.
Please, Explain me, if I am wrong.
Saesha said:
1 decade ago
Hi @Satyajeet.
It'll be (6x+6)+4/(5x+6)+4 = 11/10 because before 6 years the ratio was 6:5 but here we are taking after 4 yrs of present i.e past of 6 yrs + 4yrs (from present).
So it (6x+6)+4/(5x+6)+4 = 11/10.
It'll be (6x+6)+4/(5x+6)+4 = 11/10 because before 6 years the ratio was 6:5 but here we are taking after 4 yrs of present i.e past of 6 yrs + 4yrs (from present).
So it (6x+6)+4/(5x+6)+4 = 11/10.
Varun kumar said:
1 decade ago
@Any where ago means you have to subtract but here given mistake. If I am wrong then please explain me?
Shanky said:
1 decade ago
Want to know if 6 years ago ratio of age is taken as 6x and 5x.
Then at last why ratio of age is taken only 11 and 10 in equation.
Its the ratio of age so should be taken as 11x and 10x.
Then at last why ratio of age is taken only 11 and 10 in equation.
Its the ratio of age so should be taken as 11x and 10x.
Sng said:
1 decade ago
Let the ages of kunal and sagar be x and y years respectively.
Then,(x-6)/(y-6) = 6/5.
=>x = (6y-6)/5.
Similarly; (x+4)/(y+4) = 11/10.
=>(6y-6+20)/(5y+20) = 11/10.
=>60y+140 = 55y+220.
=>5y = 80.
=>y = 16 years.
Therefore, sagar present age is 16 years.
Then,(x-6)/(y-6) = 6/5.
=>x = (6y-6)/5.
Similarly; (x+4)/(y+4) = 11/10.
=>(6y-6+20)/(5y+20) = 11/10.
=>60y+140 = 55y+220.
=>5y = 80.
=>y = 16 years.
Therefore, sagar present age is 16 years.
Darshana said:
1 decade ago
Why we have added 6 years instead of deducting as it is given that 6 years ago?
Kishori SK said:
1 decade ago
6 years ago itself the ages are 6x, 5x respectively. Then hence 6 years it becomes 6x+6, 5x+6 right?
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