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'.

Problem: a and b can together finish a work in 40 days . they worked together for 10 days and then b left . after another 18 days , a finished the remaining work . in how many days a alone can finish the job ? 
Options: a ) 10 , b ) 24 , c ) 60 , d ) 30 , e ) 20
b

Problem: calculate how many days it will take for 5 boys to paint a 30 m long fence if 2 boys can paint a 20 m long fence in 3 days , 
Options: a ) 6.80 days , b ) 4.80 days , c ) 3.80 days , d ) 2 days , e ) 1.80 days
e

Problem: if a clock strikes 12 in 33 seconds , it will strike 6 in how many seconds ? 
Options: a ) 33 ⁄ 2 , b ) 15 , c ) 12 , d ) 22 , e ) none of these

b