Seja E a expressão que queremos calcular:
Answer:
The easiest approach is to realise that one hour is 3 times longer than 20 minutes. The longer the time, the more they will pave.
215 of a mile, in 20 minutes, how much in 60 minutes?#
They will pave 3 times more.
215×31=615 of a mile
615=25 of a mile
You could also use the 'unitary method' where you find out how much they pave in ONE minute (divide by 20) and them multiply by 60 to find how much in one hour.
Look at what happens:
215÷20×60
=215×120×603
=215×3 ← exactly the same maths.
=25
We all know about the bell curve i.e. normal distribution curve. It is centered about the mean and spread equally on each side.
We describe the area of the curve with the help of standard deviations.
With in 1 standard deviation about the mean i.e. from -1 s.d. (left of mean) to +1 s.d. (right of mean), it covers 68% of the total area of curve.
So, the data that falls outside 1 standard deviation of the mean would be equal to (100% - 68%) i.e. 32%.
So, 32% is the final answer.
Check the picture below.
recall that negative angles go "clockwise".
Answer:
You need to choose B as your answer