Risteen Telephone Services Ltd. (Risteen) designs and installs telephone systems for commercial customers. For example, in December 2015 Risteen signed a contract with Yarm Telemarketing Systems Ltd. (Yarm) to design and install a phone system for Yarm’s new call centre in New Brunswick. The following events pertain to the contract with Yarm:

i. December 13, 2015: The contract between Risteen and Yarm is signed. Yarm will pay \($550,000\) for the system that will cost Risteen \($300,000\) to design, produce, and install. The contract provides an 18-month warranty for any repairs or adjustments required. Yarm will pay within 90 days of the completed system installation.

ii. October 15, 2016: Installation of the system is completed.

iii. December 12, 2016: Warranty work costing \($35,000\) is performed.

iv. January 8, 2017: Risteen receives payment in full from Yarm.

v. April 15, 2017: Warranty expires.

Required

Prepare the journal entries required for the above events assuming the following:

a. Revenue is recognized when the contract is signed.

b. Revenue is recognized when installation of the system is complete.

c. Revenue is recognized when cash is collected.

d. Revenue is recognized when the warranty period expires.