Answer:
The birth year of Sumi is [tex]2045[/tex]
Step-by-step explanation:
Let
x------> the age of Sudha in 2055
y-----> the age of Sumi in 2055
we know that
[tex]x=2.5y[/tex] -----> equation A
[tex](x+15)=2(y+15)-10[/tex] -----> equation B
Substitute equation A in equation B and solve for y
[tex](2.5y+15)=2(y+15)-10[/tex]
[tex](2.5y+15)=2y+30-10[/tex]
[tex]2.5y-2y=30-10-15[/tex]
[tex]0.5y=5[/tex]
[tex]y=10[/tex]
Find the value of x
[tex]x=2.5(10)=25[/tex]
The birth year of Sumi is
[tex]2055-10=2045[/tex]