Form the pair of linear equations in the following problems, and find their solutions (if they exist) by the elimination method :
A lending library has a fixed charge for the first three days and an additional charge for each day thereafter. Saritha paid Rs 27 for a book kept for seven days, while Susy paid Rs 21 for the book she kept for five days. Find the fixed charge and the charge for each extra day
Solution
Let the fixed charge for first three days and each day charge thereafter be Rs x and Rs y respectively. According to the given information.
x + 4y = 27 ... (1)
x + 2y = 21....(2)
Subtracting equation (2) from equation (1), we obtain
2y = 6
y = 3 ....(3)
Substituting in equation (1), we obtain
x + 12 = 27
x = 15
Hence, fixed charge = Rs 15 And Charge per day = Rs 3
