You have now gone through the agony of processing the sample and have had it analyzed at the Purdue PRIME lab. They report back to you (months later) a concentration from which you calculate that the concentration of ¹⁰Be is 6.1x10⁵ 

atoms/gm of quartz. How long has the boulder been exposed to cosmic rays – in other words, how old is the moraine? Do the calculation in two ways:

i) Assuming that there is no decay of ¹⁰Be over the age of the boulder.

ii) Taking into account radioactive decay. Here you will have to use a slightly modified equation to back out the age. See the text for guidance.