Jambmaths question:
x varies directly as the product of u and v and inversely as their sum. If x =3 when u = 3 and v =1. What is the value of x if u = 3 and v =3
Option A:
3
Option B:
4
Option C:
6
Option D:
9
Jamb Maths Solution:
$\begin{align} & x\propto \frac{uv}{u+v} \\ & x=\frac{kuv}{u+v} \\ & \text{When }u=3,v=1,x=1 \\ & 3=\frac{k(3)(1)}{3+1} \\ & 3=\frac{3k}{4} \\ & k=4 \\ & \text{When }u=3,\text{ }v=3 \\ & x=\frac{4\times 3\times 3}{3+3}=\frac{36}{6}=6 \\\end{align}$
Jamb Maths Topic:
Year of Exam: