Given:
Mark loaded 80 boxes in 4 hour shift
Question
Avg mean of weight during shift?
Statement 1: During the first 2 hours of the shift, the average (arithmetic mean) weight of the boxes Mark loaded was 20 kilograms.
In first 2 hours of 4 hours shift he loaded boxes of avg weight 20 kg. But we dont know if his rate of work was similar throughout or different.
So this is not sufficient.Statement 2: During the last 2 hours of the shift, the average (arithmetic mean) weight of the boxes Mark loaded was 30 kilograms.
Same reason, we know last 2 hours but no idea on what was his rate of of work in first 2 hours.
So this is not sufficient. Combine:We know in first 2 hours he loaded boxes weighing 20kg avg, In last 2 hours he loaded boxes weighing 30kg avg.
But we dont know the quantity of how many boxes were loaded in each hour or we dont know the total weight of 80 goods.
What if he loaded 50 boxes in first 2 hours then 30 in next 2 hours
his rater will be 100+90/4=190/4=47.5 kg
If he loads 40 boxes in first 2 hours and 40 in next two hours
His rate will be 80+120/4=200/4=50 kg/box
So we cannot determine the exact weight.
So no statement is sufficient.Answer E Bunuel
Over a 4-hour shift, Mark loaded a total of 80 boxes into a truck. What was the average (arithmetic mean) weight of the boxes he loaded during the shift?
(1) During the first 2 hours of the shift, the average (arithmetic mean) weight of the boxes Mark loaded was 20 kilograms.
(2) During the last 2 hours of the shift, the average (arithmetic mean) weight of the boxes Mark loaded was 30 kilograms.