They say the first year of a dog's life equals 15 human years. The second year of a dog's life equals 9 human years and after that, every year of a dog's life equals 5 human years. According to this logic, how many human years has my 10-year-old dog lived?
If your dog is 10 years old then in his first year of life he lived 1*15 = 15 human years.
In his second year of life, he lived 1*9 = 
<gadget id="calculator">1*9</gadget>
<output>9</output>
9 human years.
We need to calculate his remaining years or 10-2 = 
<gadget id="calculator">10-2</gadget>
<output>8</output>
8 years of dog life into human years.
If 1 year of dog life after the 2 years equates to 5 human years, then 8 years of dog life equals 8*5 = 
<gadget id="calculator">8*5</gadget>
<output>40</output>
40 human years.
In total, your dog has lived 15 + 9 + 40 = 
<gadget id="calculator">15+9+40</gadget>
<output>64</output>
64 human years.

<result>64</result>