How long does Apple take to approve an app?

So exactly 1 week after we received the “Waiting for Review” email from Apple, we received the “In Review” notification.

The review of our Outskirts Press Free Publishing app took 4 hours and 38 minutes.  At 4:38 in the afternoon on Tuesday, one week after submitting it, we received the following notice from Apple:

Dear Outskirts Press,

The status for the following app has changed to Processing for App Store.

App Name: Outskirts Press Free Publishing App
App Version Number: X.XXXXX
App SKU: 01
App Apple ID: XXXXXXX

To make changes to this app, sign in to iTunes Connect and open the Manage Your Applications module.

If you have any questions regarding your app, click Contact Us in iTunes Connect.

Regards,

The iTunes Store Team

And then, 21 minutes later, we received this notice:

Dear Outskirts Press,

The following app has been approved. The status has changed to Ready for Sale.

If your contracts are not in effect at this time, however, your app status will be Pending Contract. You may track the progress of your contracts in the Contracts, Tax, and Banking module in iTunes Connect.

Note that it may take up to 24 hours before your app is live on the App Store. This delay is dependent upon any app availability issues.

App Name: Outskirts Press Free Publishing App
App Version Number: X.XXXXXX
App SKU: 01
App Apple ID:XXXXXXX

To make changes to this app, sign in to iTunes Connect and open the Manage Your Applications module.

If you have any questions regarding your app, click Contact Us in iTunes Connect.

Sincerely,

The iTunes Store Team