Heather helps her neighbour pick weeds out of her garden. She gets paid 5 cents for every weed she picks. On average, how many seconds can she take to pick a weed if she wants to earn $10 an hour?
In an hour, she needs to earn $10 * 100 cents / $1 = 
<gadget id="calculator">10*100</gadget>
<output>1_000</output>
1000 cents.
In an hour, she must pick 1000 cents / 5 cents = 
<gadget id="calculator">1000/5</gadget>
<output>200</output>
200 weeds.
There are 1hr * (60 minutes / 1 hr) = 
<gadget id="calculator">1*60</gadget>
<output>60</output>
60 minutes in an hour.
There are 60 minutes * (60 seconds / 1 minute) = 
<gadget id="calculator">60*(60/1)</gadget>
<output>3_600</output>
3600 seconds in an hour.
She has 3600 seconds / 200 = 
<gadget id="calculator">3600/200</gadget>
<output>18</output>
18 seconds to pick each weed.

<result>18</result>