Greg has his own dog walking business. He charges $20 per dog plus $1 per minute per dog for walking the dog. If he walks one dog for 10 minutes, two dogs for 7 minutes and three dogs for 9 minutes, how much money, in dollars, does he earn?
Single dog is $20 + (10 minutes * $1 per minute) = $
<gadget id="calculator">20+10*1</gadget>
<output>30</output>
30.
Two dogs are 2 * ($20 + (7 minutes * $1 per minute)) = $
<gadget id="calculator">2*(20+7*1)</gadget>
<output>54</output>
54.
Three dogs are 3 * ($20 + (9 minutes * $1 per minute)) = $
<gadget id="calculator">3*(20+9*1)</gadget>
<output>87</output>
87.
The total is $30 + $54 + $87 = $
<gadget id="calculator">30+54+87</gadget>
<output>171</output>
171.

<result>171</result>