Question

Mr. Kanja,Miss Kanene and Mrs Nyaga have to mark a form three math contest for 160 students. They take 5mins, 4mins, and 12mins respectively to mark a script. If they all start to mark at 9.00 am non-stop, what is the shortest time they can take to complete the marking?

Answer 1

LCM of 5, 4, 12 =60                  
In 60 mins  Kanja -12 scripts
               Kanene -15 scripts
                 Nyaga - 5 scripts
                       All -32 scripts   
 60 → 32    
  ?  → 160
       =300mins =5hrs