3. A couple wanted to invest $15 000 over the next three months, and was trying to decide whether to invest it all at once, or to allocate $5 000 at the start of every month. Describe the effect of dollar-cost averaging if the price of the investment rose from $25 per share in the first month, to $32 per share in the second month, and then fell to $20 per share in the third month before returning to its original $25 price at the end of the third month.