On interchanging, the resistances, the balance point of a meter bridge shifts to the left by 10 cm. The resistance of their series combination is 1 kΩ. How much was the resistance on the left slot before interchanging the resistances?

$\frac{X}{R} = \frac{ℓ}{(100 - ℓ)}, \frac{R}{X} = \frac{ℓ - 10}{10 - ℓ}$
And $X + R = 1000 Ω$

On interchanging, the resistances, the balance point of a meter bridge shifts to the left by 10 cm. The resistance of their series combination is $1 kΩ$ . How much was the resistance on the left slot before interchanging the resistances?