Question

One lecture at an evening course last for 1 1\2 .if the course last 30hours altogether,how many lecture are there?
(A) 45 (B) 35 (C) 20 (D)20 (E) 15

Answer 1

One lecture duration : 1 1/2 hrs = 1.5 hours  or 3/2 hours

Total course duration = 30 hours

Number of lectures * duration of each lecture = total course duration

number of lectures = total course duration / duration of each lecture
                           =  30 hours / (3/2) hours  =   30 * 2/3  = 60/3 = 20

Answer 2

Time for 1 evening course = 1.5 hr
Total course duration = 30 hr
Total lecture classes = 30/1.5
= 20 classes
(D) 20