The cost of servicing of a Maruti car at Maruti care Pvt. Ltd. is Rs. 400. Manager of service centre told me that for the second service within a year a customer can avail a 10% discount and further for third and fourth servicing he can avail 10% discount of the previous amount paid, within a year. Further if a customer gets more than 4 services within a year, he has to pay just 60% of the servicing charges on these services. A customer availed 5 services from the same servicing station, what is the total percentage discount fetched by the customer?

100 == 10%↓ (1st disc.) ⇒ 90 == 10%↓ ⇒ 81 == 10%↓ ⇒ 72.9 == 10%↓ ⇒ 60(After 5^th discount.)

Alternatively,
Amount paid in 1^st service = 100 (Assume)
Amount paid in 2^nd service = 90
Amount paid in 3^rd service = 81
Amount paid in 4^th service = 72.9
Amount paid in 5^th service = 60
Total amount paid,
= (100 +90 +81 +72.9 +60) = 403.9
Total Discount = 500 - 403.9 = 96.1
% Discount = $$\frac{{96.1 \times 100}}{{500}}$$   = 19.42%