NO!!. 29 IS HALF-LIFE!! Half-life of any radioactive substance is calculated as: ln(1/2) / k, when k is known. IF it is not known, then it is calculated as: ln(1/2) / half-life of the substance.
I think you should have Alan explain it to you if you don't understand the technical page I referred you to. http://math.usask.ca/emr/examples/expdeceg.html
P.S. The whole problem stems from the way the question is posed. When e is used, it automatically implies that you have to calculate k, so that it should read: e^(kt). When they give you the half-life, it automatically implies that you must calculate k. You can get the same result by using: 2^(-t/half-life), or: 1/2 ^ (t/half-life).