Contest #15

Dave is evaluating the effectiveness of his Google ad campaigns for his business English program. Although he is paying on a cost per click basis, he is looking to see which campaign is giving him the most impressions for the least money.

Last month, Campaign #1 cost $31.00. It had 105 clicks and 40,134 impressions.

Campaign #2 cost two point one times as #1. It had 158 clicks and had a click-through rate of zero point nine two percent.

Campaign #3 cost $12.25 less than campaign #1. It had 11.5% fewer clicks than Campaign #1, but had a higher click-through rate than Campaign #2 by zero point five four percentage points. 

Which campaign is most effective for Dave, based on a cost per 1000 impressions?

Solution to Contest #14

• Current holding in $US = $100 + Є100 x $0.75543/Є=$175.54.
• New exchange rate = 0.75543 x (1— 0.026) = 0.73579.
• Future holdings in $US = $100 + Є100 x 0.73579 = $173.58.
• % Change = (173.58 — 175.54) / 175.54 x 100% = —1.1%.

His holding will have dropped by 1.1% by next week if this rate change occurs.