SOLUTION: 1) The average of a train running at a speed of 30km/hr during the first 100 kilometers, at 40km/h during the second 100 kilometers and at 50km/h during the last 100 kilometers is

Question 1081217: 1) The average of a train running at a speed of 30km/hr during the first 100 kilometers, at 40km/h during the second 100 kilometers and at 50km/h during the last 100 kilometers is nearly?
2) it rained as much on Wednesday as on all the others day of the week combined. If the average rainfall for the whole week was 3cm, how much did it rain on Wednesday?
3) The average of 6 observation is 12. A new seventh observation is included and the new average is decreased by 1. The seventh observation is.
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
1) The average of a train running at a speed of 30km/hr during the first 100 kilometers, at 40km/h during the second 100 kilometers and at 50km/h during the last 100 kilometers is nearly?
"nearly" is not clearly defined.
The total time = 100/30 + 100/40 + 100/50 = 10/3 + 2.5 + 2 hours.
= 37/6 hours
Avg speed = 300/(47/6) = 1800/47 km/hr
=============================
2) it rained as much on Wednesday as on all the others day of the week combined. If the average rainfall for the whole week was 3cm, how much did it rain on Wednesday?
Avg*7 = 21 for the week
--> 10.5 in 6 days + 10.5 on Wednesday
=====================================
3) The average of 6 observation is 12. A new seventh observation is included and the new average is decreased by 1. The seventh observation is.
6*12 = 72
(72 + x)/7 = 11
x = 5

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