KCET 2004 Physics Solved Paper

An unknown resistance R1 is connected in series with a resistance of 10Ω. This combination is connected to one gap of a metre bridge while a resistance R2 is connected in the other gap. The balance point is at 50‌cm. Now, when the 10Ω resistance is removed the balance point shifts to 40‌cm. The value of R1 is (in ohm)