One of your clients wants to know why a campaign went over the specified daily budget several days in a row. What would you explain to your client about how the AdWords system works?

 

• AdWords automatically increases the maximum cost-per-click (CPC) bid to show an ad higher in Google search results
• Due to changes in traffic, AdWords allows up to 20% more impressions in a day than the budget specifies
• To show an ad more often, AdWords charges more than the average daily budget amount multipled by 30.4
• Due to changes in traffic, AdWords allows up to 20% more clicks in a day than the budget specifies. However, in any given month, AdWords never charges more than the average daily budget amount multiplied by 30.4

Correct answer is:

• Due to changes in traffic, AdWords allows up to 20% more clicks in a day than the budget specifies. However, in any given month, AdWords never charges more than the average daily budget amount multiplied by 30.4

Explanation: When your ads are shown more often, your total daily cost might be up to 20% more than your average daily budget. However, you won’t be charged more than your average daily budget multiplied by the average number of days in a month (30.4).

Read more here: https://support.google.com/adwords/answer/2375423?hl=en