Percent problems

9000085307

Level: 
B
A machine fills \(2\: 000\) bottles per hour. As a consequence of technical problems, the efficiency of the machine decreased by \(10\, \%\). How many bottles can be filled by the machine with the mentioned technical problems during a time period of \(8\) hours?
\(14\: 400\)
\(13\: 800\)
\(14\: 500\)
\(15\: 200\)

9000085310

Level: 
B
The pad in the form of (not necessarily regular) octagon is manufactured from a square. The side of the square is \(4\, \mathrm{cm}\). An isosceles right triangle of the hypotenuse \(1\, \mathrm{cm}\) is removed from each corner of the square which results in the desired octagon. How much of the material of the initial square goes to the waste?
\(12.5\, \%\)
\(10\, \%\)
\(15\, \%\)
\(20\, \%\)

1003083304

Level: 
C
The initial price of ice bags was \( 24.20 \) zlotys. Now, you can buy \( 22 \) ice bags (which is \( 10\% \) more than before) for the same price. What is the percentage decrease in the price of one ice bag?
by app. \( 9\% \)
by app. \( 8\% \)
by \( 10\% \)
by \( 2.2\% \)

1003083306

Level: 
C
In a certain school, grades are given according to the rules listed below: \[\begin{array}{|c|c|} \hline \text{The percentage of the points gained} & \text{grade} \\\hline 0\%\text{ to } 49\% & 1 \\\hline 50\% \text{ to } 59\% & 2 \\\hline 60\% \text{ to } 79\% & 3 \\\hline 80\% \text{ to } 89\% & 4 \\\hline 90\% \text{ to } 94\% & 5 \\\hline 95\% \text{ to } 100\% & 6 \\\hline \end{array}\] Krysia gained \( 39 \) points from the history test. There were only \( 2 \) percentage points missing for her to get grade \( 4 \). What was the total amount of points one could get from the test?
\( 50 \) points
\( 41 \) points
\( 45 \) points
\( 55 \) points