Concept:Set up equations from the given totals and solve for C using elimination.Explanation:Let the amounts with A, B, and C be A, B, C (in Rs.).From the problem:A+C=400B+C=700A+B+C=1000Add the first two equations:(A+C)+(B+C)=400+700⇒A+B+2C=1100Now subtract the total equation (A+B+C=1000) from this result:(A+B+2C)−(A+B+C)=1100−1000⇒C=100Thus, C has Rs. 100.Answer:Rs. 100