Question

To extract the pollution-free fuel from the planet Ceria X-3, a pipe of length 12.1 metres is used. If the pipe has a valve at every 11 centimetres, the total number of valves would be ____.

• A. 11
• B. 1100
• C. 110
• D. 121

Answer 1

The correct option is C 110

Total length of the pipe = $12.1$ metres.
The pipe has a valve at every 11 centimeters.

First, convert both the lengths to the same unit.


Converting metres to centimetres,
$1m=1\times 100cm=100cm$.

So, $12.1m=12.1\times 100cm=1210cm$.

To find the total number of valves, divide $1210$ by $11$.

Therefore, rewrite the equation as $1210cm÷11cm$.

$1210$ can be written as $100+200+10$.

So, calculating $1210cm÷11cm$ using the box method,


Calculating the sum of the partial quotients, $90+10+10=110$.

Hence, the final quotient is $110$.

Therefore, the pipe has a total of $110$ valves in it.