Lane promised to lend Turner $240,000 if Turner obtained sureties to secure the loan. Turner agreed with Rivers, Clark, and Zane for them to act as co-sureties on the loan from Lane. The agreement between Turner and the co-sureties provided that compensation be paid to each of the co-sureties. The agreement further indicated that the maximum liability of each co-surety would be as follows: Rivers $240,000, Clark $80,000, and Zane $160,000. Lane accepted the commitments of the sureties and made the loan to Turner. After paying ten installments totaling $100,000, Turner defaulted. Clark's debts, including the surety obligation to Lane on the Turner loan, were discharged in bankruptcy. Later, Rivers properly paid the entire outstanding debt of $140,000. What amount may Rivers recover from Zane?