Aptitude Day 152

Problems on average:                        

    

1. In James opinion, his weight is greater than 45kg but less than 50kg. His brother doesn’t agree with James and he thinks that his weight is greater than 40kg but less than 55kg. His mother’s view is that his weight cannot be greater than 48kg. If all of them are correct in their estimation, what’s the average different probable weights of James?

Solution:

                 Let James weight X kg.

                 Given conditions:

                        45 < X <50

                        40 < X <55

                        X < 48

              46 and 47 are the values satisfied from the above conditions.

  

              Average = Sum of observations/ Number of observations

                              = (46+47)/2

                              = 93/2

                              = 46.5 kg.

       

2. The average of 10 numbers is zero. Of them, at the most, how many may be greater than zero?

Solution:

                 Average = 0.

                Average = Sum of observations/ Number of observations

                             0 = Sum of observations /20

              

                 Hence, Sum of observations will be 0.

                 It’s quite possible that 9 of these numbers may be positive and if their sum is x, then 10^th number is –x.  So, at the most 9 numbers may be greater than 0.