 
<translate> Otu nkịta bụ $20 + (10 nkeji * $1 kwa nkeji) = $30. Nkịta abụọ bụ 2 * ($20 + (7 nkeji * $1 kwa nkeji)) = $54. Nkịta atọ bụ 3 * ($20 + (9 nkeji * $1 kwa nkeji)) = $87. Ngụkọta bụ $30 + $54 + $87 = $171. Azịza ikpeazụ ya bụ: 171. <eng> Single dog is $20 + (10 minutes * $1 per minute) = $30. Two dogs are 2 * ($20 + (7 minutes * $1 per minute)) = $54. Three dogs are 3 * ($20 + (9 minutes * $1 per minute)) = $87. The total is $30 + $54 + $87 = $171.
The final answer: 171. 