Subject: General Aptitude · Chapter: Area · Exam: 2007 · Marks: · Difficulty:
The circumference of the back-sided wheel of a vehicle is 1 m greater than that of front side wheel. To travel 600 m, the front wheel rotates 30 times more than the back wheel. The circumference of the front wheel is
(a)2 m
(b)4 m
(c)5 m
(d)None of these
Answer
Answer (as printed): B
Explanation
Let the circumference of front wheel be $x$ metres. Then, circumference of rear wheel $=(x-1)$ metres. $$\begin{aligned} \therefore \frac{600}{x}-\frac{600}{(x+1)}=30 & \Rightarrow \frac{1}{x(x+1)}=\frac{1}{20} \\ & \Rightarrow x(x-1)=20 \Rightarrow\left(x^{2}+x-20=0\right. \\ & \Rightarrow(x+5)(x-4)=0 \Rightarrow x=4 \mathrm{m} . \end{aligned}$$