A and B are two fixed points 5 cm apart and C is a point on AB such that AC is 3 cm. If the length of AC is increased by 6%, the length of CB is decreased by :

Answer: Option D

Original length of AB = 5 cm
Original length of AC = 3 cm
Original length of CB = (5 - 3) cm = 2 cm
New length AC :
= 106% of 3 cm
= $$\left(\frac{106}{100}\times 3\right)$$  cm
= 3.18 cm
New length of CB :
= (5 - 3.18) cm
= 1.82 cm
Decrease in length of CB :
= (2 - 1.82) cm
= 0.18 cm
∴ Decrease % :
= $$\left(\frac{0.18}{2}\times 100\right)\%$$
= 9%