In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Q: Problem: 6 bells commence tolling together and toll at the intervals of 24 , 68 , 1012 seconds resp . in 60 minutes how many times they will toll together . 
Options: a ) 15 , b ) 16 , c ) 30 , d ) 31 , e ) none of these

A: d
****
Q: Problem: a cistern of capacity 8000 litres measures externally 3.3 m by 2.6 m by 1.2 m and its walls are 5 cm thick . the thickness of the bottom is : 
Options: a ) 90 cm , b ) 2 dm , c ) 1 m , d ) 1.1 cm , e ) none of these

A: b
****
Q: Problem: how many seconds will a train 100 meters long take to cross a bridge 150 meters long if the speed of the train is 42 kmph ? 
Options: a ) 21.4 sec , b ) 77 sec , c ) 25 sec , d ) 18 sec , e ) 17 sec

A:
a
****