arithmetic averages questions and answers paper 286 - skillgunNote: Paper virtual numbers may be different from actual paper numbers . In the page numbers section website displaying virtual numbers .
The average of fifteen numbers is 0. In those 15, at the most, how many may be greater than zero?
Average of 15 numbers = 0
Sum of 15 numbers =(0 x 15) =0.
It is quite possible that 14 of these numbers may be positive and if there sum is a, then 15th number is (-a).
The average of six numbers is S and the average of three of these is T.If the average of the remaining three is U, then
S= T + U
2S= T + U
S= 2T + 2U
Clearly, we have S =(3T+3U/6)
or 2S= T + U
A motorist travel to a place 220 km away at an average speed of 72 km/hr and returns at 55 km/hr.His average speed for the whole jouney in km/hr is
Average Speed = (2xy/x +y )km/hr =(2x72 x55/ 72+55) = 7920/127 = 62.36 km/hr.
The average age of a husband and his wife was 24.5 years at the time of their marriage. After five years they have a 3 years old child.The average age of the family now is
Sum of the present ages on husband, wife and child =(24.5x2+5x2)+3 = 62 years
Required average = (62/3) = 20.66 years.
The average weight of six oarsmen in a boat is increased by 1.2 kg when one of the crew, who weighs 64 kg is replaced by a new man. find the weight of the new man.
Total weight increased = (1.2 * 6) kg = 7.2 kg.
Weight of the new man = (64 + 7.2) kg = 71.2 kg.
The average age of the mother and her six children is 12 years which is reduced by 5 years if the age of the mother is excluded. How old is the mother?
Therefore age of the mother
= ( 12 × 7 – 7 × 6)
= 42 years.
In the first 20 overs of a cricket game, the run rate was only 4.2. What should be the run rate in the remaining 30 Overs to reach the target of 324 runs?
Required run rate = (324 - 4.2 × 20 ) = 240/ 30 = 8.
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