In January 2009, Atta, a business consultant, won a lucrative contract with MUCG Ltd to provide them with a highly specialized computer system. The terms of the contract required the system to be fully operational by 30 May 2009 subject to a penalty of GH¢10,000 for every day's delay. Atta entered into three subcontracts. One was with Boateng to provide the software forte new system, a second with Darko to provide the necessary computer hardware and a third mith Looto write a manual explaining the operation of the new system. All of these tasks were to be caused by 23 May 2009. Boateng, Darko and Ebo were each to receive GH¢50,000 for their work. 

At the end of March, Boateng told Atta that he would not completa che software in time unless Atta agreed to increased his payment by a further GH¢10,000 ta agreed to pay the increased sum in order to ensure that the job was done on time. However, he mough it was only fair that he should increase the money promised to the others, so he promisochtend bonus of GH¢10,000 if the job was done on time. At the same time he asked he could produce his manual by 16 May 2009 so that he could demonstrate it in advance to the managers of MUCG Ltd. 

In the event, all three completed their tasks 10 May 2009 and the system was successfully installed before Atta's contractual deadlie with Utd. However, Atta has now refused to make any additional payments beyond the Original contractual price to Boateng, Darko or Ebo. rial Questions 

Required: 

Advise Boateng, Darko and the whether they have any rights in law to enforce Atta's promise to pay them an extra GH¢10 go.