Ques:- The average age of 12 students is 20 years. If the age of one more student is included, the average decreases by 1. What is the age of the new student?
A. 5 years
B. 6 years
C. 7 years
D. 9 years
Ques:- A train of length 150 m takes 40.5 seconds to cross a tunnel of length of 300 m. The speed of the train (in km/hr) is
A. 13.33
B. 26.67
C. 38.32
D. 40
Ques:- Five years ago, the total of the ages of a father and his son was 40 years. The ratio of their present ages is 4 : 1. What is the present age of the father?
A. 20 years
B. 30 years
C. 40 years
D. 50 years