Ques:- Find out the wrong number in a given series.
3, 7, 15, 39, 63, 127, 255, 511
3, 7, 15, 39, 63, 127, 255, 511
A. 7
B. 15
C. 39
D. 67
Ques:- A train 280 m long is moving at 60 km/hr. Time taken by the train to cross a tunnel 220 m long is
A. 15 sec
B. 20 sec
C. 25 sec
D. 30 sec