Step-by-step explanation:
Let,
- x = Kevin's age
- y = Kevin's mother's age
Given that,
Kevin's age + Mother's age = 61
x + y = 61 [tex]\rightarrow[/tex] required equation for a)
[tex]\rule{150pt}{2pt}[/tex]
Now, we have two equations.
y - 3x = 1 -------(1)
y + x = 61 --------(2)
On solving them (using the substitution method),
[tex]\left. \begin{cases} { y-3x = 1 } \\ { y+x=61 } \end{cases} \right.[/tex]
Take ----(1)
[tex]y-3x=1 \\y=3x+1[/tex]
Now, substitute the value of y in ----(2)
[tex]y + x = 61\\3x+1+x=61 \\4x+1=61 \\4x=60 \\x = 15[/tex]
Substitute the value of x in -----(1),
[tex]y=3\times 15+1 \\y= 45+1\\y = 46[/tex]
So,
[tex]\boxed{\bf\:x = 15, \:y = 46}[/tex]
Now, by graphing them (see the attachment), the point of intersection is O (15, 46). Hence, from this we can infer that, Kevin is 15 years old while his mother is 46 years old. [tex]\rightarrow[/tex] answer for b)
[tex]\rule{150pt}{2pt}[/tex]
