Please solve question number 10 b. Its answer is 4 years, 5 years.
It is important for my exam. ASAP
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kvnmurty:
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Answered by
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Ages of Mrs Tandon and her sons in years:
T, S1, and S2 respectively.
Given:
S1 = S2 + 1 ---(1)
T = S1² + S2² ---- (2)
After 4 years: their ages increase by 4 years.
T + 4 = 5 * (S1 + 4) ---(3)
T = 5 S1 + 16
T = 5 (S2 +1) + 16 = 5 S2 + 21 ---(4)
From (1) and (2):
T = (S2+1)² + S2² = 2 S2² + 2 S2 + 1 --(5)
From (4) and (5)
5 S2 + 21 = 2 S2² + 2 S2 + 1
2 S2² - 3 S2 - 20 = 0
2 * (-20) = -40 ... factors are -8 * 5 Sum = - 3
(2 S2 + 5) (S2 - 4) = 0
So S2 = 4 years, reject S2 = -5/2 as age is positive.
So S1 = 5 years.
Mrs Tandon's age : T = S1² + S2² = 41 years.
T, S1, and S2 respectively.
Given:
S1 = S2 + 1 ---(1)
T = S1² + S2² ---- (2)
After 4 years: their ages increase by 4 years.
T + 4 = 5 * (S1 + 4) ---(3)
T = 5 S1 + 16
T = 5 (S2 +1) + 16 = 5 S2 + 21 ---(4)
From (1) and (2):
T = (S2+1)² + S2² = 2 S2² + 2 S2 + 1 --(5)
From (4) and (5)
5 S2 + 21 = 2 S2² + 2 S2 + 1
2 S2² - 3 S2 - 20 = 0
2 * (-20) = -40 ... factors are -8 * 5 Sum = - 3
(2 S2 + 5) (S2 - 4) = 0
So S2 = 4 years, reject S2 = -5/2 as age is positive.
So S1 = 5 years.
Mrs Tandon's age : T = S1² + S2² = 41 years.
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:-)
Thank you sir.
Can this be solved using only one variable?
instead of three?
Ok I understood the answer. Thank you once again!
Good night sir. :-)
to solve by one variable... choose S2.. write S2^2 + (S2+1)^2 + 4 = 5 * (S2 +1 + 4)
I did not know whether to give a detailed explanation or solve it in fewer steps.
Ok I understood.
Answered by
14
I have explained the solution in the given pics .
Do ask me if any doubt occurs to you.
Do ask me if any doubt occurs to you.
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