For a triangle ABC, D and E are two points on AB and AC such that AD = 1/4 AB, AE = 1/4 AC. If BC = 12 cm, then DE is :

Answer: Option C

According to question,

By using B.P.T
$$\begin{array}{rl}& \frac{AD}{AB}=\frac{AE}{AC}=\frac{DE}{BC}\\ & \frac{AD}{AB}=\frac{DE}{BC}\\ & \Rightarrow \frac{1}{4}=\frac{DE}{12}\\ & \Rightarrow DE=3\text{cm}\end{array}$$