All of the plaintiffs' claims are dismissed.

The costs of lawsuit shall be borne by the plaintiffs.

On July 15, 2008, the Defendant, as a public corporation established under the Korea Road Corporation Act, announced a public tender for the “C extended construction works” on July 15, 2008. The Plaintiffs organized a common water supply system and participated in the tender of D Section, and the lowest price was selected as successful bidders (hereinafter “instant construction works”). The Plaintiffs and the Defendant concluded the first construction contract, which is the next number of contracts for the construction work, from April 6, 2009 to July 14, 2009, with the contract amount of KRW 1 billion, and the construction period of KRW 1 billion, and from April 6, 2009 to July 14, 2009, the first construction contract, which is the next number of contracts for the construction work, was additionally stated in the contract amount of KRW 79.64 billion, and the total construction period of KRW 1,200,000,000,000 for each of the instant construction contracts (hereinafter referred to as “the second construction contract amount”).

(2) For long-term continuous construction works, the total contract period shall be determined by summing up the number of days for the period of annual contract implementation, but shall include holidays during the period.

In such cases, the annual contract implementation period shall be calculated on the basis of the beginning date of the annual construction work, and the contracting officer shall determine it within the scope of the total contract period in consideration of the scheduled construction process of the relevant construction work, the forecast of the year, etc.

(7) In cases of adjusting the contract amount under paragraphs (1) through (6), in accordance with the general conditions of the construction contract (Adjustment of the contract amount due to a modification of a design), our Corporation shall adjust the contract amount within 30 days from the date on which the party under the contract is requested to adjust the contract amount.

(9) The former part of paragraph (7) shall be applicable.