Question

a lending library has a fixed charge for the first three days and an additional charge for each day thereafter and saritha paid rs 27 for a book kept for seven days while susy paid 21 rs for a book kept for five days find the fixed charge and the charge for each extra day

Answer 1

here's your answer hope it helped.
All the best for exams!

Answer 2

it is very easy answer. you have to take fixed charges as X and additional charge as y. you got 2 equations and then evaluating them answer will come. fixed charges=₹5 ×3 =₹15 (it is for 3 days) and additional charges =₹3