Question

The ratio of the radius of the back wheel of a tractor to that of the front wheel is $7:5$. The diameter of the back wheel is $70$ cm What is the distance moved by the front wheel after it has turned $10$ rounds? (Take $\pi =\frac{22}{7}$ Round off your answer to the nearest whole number)

• A. $1440cm$
• B. $1500cm$
• C. $1571cm$
• D. $1600cm$

Answer 1

The correct option is C $1571cm$

The ratio of the radius of the back wheel of a tractor to that of the front wheel be $7x:5x$. The diameter of the back wheel is $70cm$. Hence the radius of the front wheel will be $25cm$.
Circumference of the front wheel = $2\pi \left(25\right)=2\ast \frac{22}{7}\ast 25=157.14$.
Hence the distance moved by the front wheel after it has turned $10$ rounds is $157.14\ast 10=1571.4cm$.