Let B be Binu's current age.
Let M be Manu's current age.
From the problem, we get two equations:
"Manu’s age is 6 times Binu's age"
M=6B
"15 years hence Manu will be 3 times as old as Binu"
M+15=3(B+15)
We can substitute the value of M from the first equation (M=6B) into the second equation:
6B+156B+15amp;=3(B+15)amp;=3B+45
Now, isolate the term with B:
6B−3B3BBBamp;=45−15amp;=30amp;=330amp;=10