Differentiate :
Answers
Answer:
\large \clubs \: \bf Given : -♣ Given: −
The sum of ages of father and daughter is 52 years.
Six years ago, the product of their ages was 175.
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\large \clubs \: \bf To \: Find : -♣ ToFind: −
Their Present Ages
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\large \clubs \: \bf Solution : -♣ Solution: −
Let,
Present Age of Father = x years
Present Age of Daughter = y years
✏ According To Question :
\begin{gathered} \text{Sum of Their Ages = 52 years} \\ \end{gathered}
Sum of Their Ages = 52 years
\begin{gathered}:\longmapsto \text{x + y = 52} \\ \end{gathered}
:⟼x + y = 52
\begin{gathered}:\longmapsto \bf x = 52 - y \: - - - (1) \\ \end{gathered}
:⟼x=52−y−−−(1)
《 6 Years Ago 》
Age of Father = (x - 6) years
Age of Daughter =(y - 6) years
✏ According To Question :
\begin{gathered} \red{ (\text x - 6)(\text y - 6) = 175} \\ \end{gathered}
(x−6)(y−6)=175
\begin{gathered}:\longmapsto\text x\text y - 6\text x - 6\text y + 36 = 175 \\ \end{gathered}
:⟼xy−6x−6y+36=175
\begin{gathered}:\longmapsto\text x\text y - 6\text x - 6\text y = 175 - 36 \\ \end{gathered}
:⟼xy−6x−6y=175−36
\begin{gathered}:\longmapsto \bf xy - 6x - 6y = 139 \: - - - (2) \\ \end{gathered}
:⟼xy−6x−6y=139−−−(2)
✏ Putting (1) in (2) :
\begin{gathered}:\longmapsto(52 -\text y)\text y - 6(52 - \text y) - 6\text y = 139 \\ \end{gathered}
:⟼(52−y)y−6(52−y)−6y=139
\begin{gathered}:\longmapsto52\text y - \text y {}^{2} - 312 + \cancel{6\text y} - \cancel{6\text y} = 139 \\ \end{gathered}
:⟼52y−y
2
−312+
6y
−
6y
=139
\begin{gathered}:\longmapsto52\text y - \text y {}^{2} = 139 + 312 \\ \end{gathered}
:⟼52y−y
2
=139+312
\begin{gathered} \bf \red{:\longmapsto{{y}^{2} - 52y + 451 = 0 }} \\ \end{gathered}
:⟼y
2
−52y+451=0
\begin{gathered}:\longmapsto\text{y}^{2} - 11\text y - 41\text y + 451 = 0 \\ \end{gathered}
:⟼y
2
−11y−41y+451=0
\begin{gathered}:\longmapsto\text y(\text y - 11) - 41(\text y - 11) = 0 \\ \end{gathered}
:⟼y(y−11)−41(y−11)=0
\begin{gathered}:\longmapsto(\text y - 11)(\text y - 41) = 0 \\ \end{gathered}
:⟼(y−11)(y−41)=0
\begin{gathered}\purple{ \large :\longmapsto \underline {\boxed{{\bf y = 11 \: or \: y = 41} }}} \\ \end{gathered}
:⟼
y=11ory=41
☆ When y = 11 :-
\text x = 52 - 11 \: \: \: \: \bf \{using \: (1) \}x=52−11{using(1)}
\begin{gathered}\purple{ \Large :\longmapsto \underline {\boxed{{\bf x = 41} }}} \\ \end{gathered}
:⟼
x=41
☆ When y = 41 :-
\begin{gathered}\text x = 52 - 41 \\ \end{gathered}
x=52−41
\purple{ \Large :\longmapsto \underline {\boxed{{\bf x = 11} }}}:⟼
x=11
As x is Age father and y is age of daughter
\LARGE \orange{\bf\therefore\:\: x > y}∴x>y
Hence,
\purple{ \large \underline {\boxed{{\bf x = 41 \: \: and \: \: y =11 } }}}
x=41andy=11
Therefore,
\begin{gathered} \pink{\begin{cases} \bf Age \: of \: Father = 41 \: years \\ \\ \bf Age \: of \: Daughter = 11years \end{cases}}\end{gathered}
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AgeofFather=41years
AgeofDaughter=11years
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Question :
- calculate dy/dx.