AVERAGES

AVERAGES

1. Average = [ Total of observations/No.of observations ] 2.(i)When a person joins a group in case of increasing average Age         weight of new comer  = [ (Previous Age + No.of persons) * Increase in Avg ]    (ii)In case of decreasing Average, Age (or) weight of new comer  = [ (Previous Age - No.of persons) * Decrease in Avg ] 3.When a persom leaves a group and another person joins the group in the     place of person left, then    (i)In case of increasing average, Age (or) weight of new comer  = [ (Age of person left + No.of persons) * Increase in Avg ]    (ii)In case of decreasing Average, Age (or) weight of new comer  = [ (Age of person left - No.of persons) * Decrease in Avg ] 4.When a person leaves the group but no body joins this group, then    (i)In the case of increasing Average, Age (or) weight of man left  = [ (Previous Age - No.of present persons) * Increase in Avg ]    (ii)In case of decreasing Average, Age (or) weight of new comer  = [ (Previous Age + No.of present persons) * Decrease in Avg ] 5.If a person travels a distance at a speed of x Km/hr returns to the original    place of y Km/hr then average speed is [ 2.x.y/(x+y) ] 6.If half of the journey is travelled at speed of x km/hr and the next half at a    speed of x km/hr. Then average speed during the whole journey is [ 2.x.y/(x+y) ] 7.If a person travels 3 equal distances at a speed of x Km/hr,    y Km/hr,z km/hr.Then average speed during whole journey is [ 3.x.y/(x.y+y.x+z.x) ] 8. A½ [ 3.x.y/(2x*y) ] 9.A½ [ 3*L/[ (L/S1)+(L/S2)+(L/S3) ] 10.A½ 4L/[ (L.S1)+(L/S2)+L/S3)+(L/S4) ] 11.A½ 1/[ (x/100) * (1/S1) ] + [y/100) * (1/S2) ] + [ (z/100)*(1/S3) ]