Directions: In a college, 120 students come in canteen for lunch, where coffee, ice-cream and tea are available at Rs 15, Rs 20 and Rs 10 respectively. 45 students serve ice-cream, 30 students serve tea and only 25 prefer coffee. 20 students serve ice-cream and tea. 15 students serve ice-cream and coffee. 5 students take all three and 5 students take coffee and tea but do not take ice-cream.