Three years from now, Tully will be twice as old as Kate. How old was Tully a year ago if Kate is now 29 years old?
Three years from now, Kate will be 29 years + 3 years = 
<gadget id="calculator">29+3</gadget>
<output>32</output>
32 years old.
So by that time, Tully will be 32 years x 2 = 
<gadget id="calculator">32*2</gadget>
<output>64</output>
64 years old.
This means, Tully is 64 years - 3 years = 
<gadget id="calculator">64-3</gadget>
<output>61</output>
61 years old now.
Therefore, Tully was 61 years - 1 year = 60 years old last year.

<result>60</result>