Question : Before the battle, the ratio of tanks to planes in an army was 5 : 3. During the war, 1000 tanks were destroyed and 800 planes were destroyed. The ratio of tanks to planes became 2 : 1, what was the number of tanks after the war?

Option 1: 2000

Option 2: 1000

Option 3: 3000

Option 4: 4000

Question : The perimeter of an equilateral triangle is equal to the circumference of a circle. The ratio of their areas is: ( Use $\pi =\frac{22}{7}$)

Option 1: $22 : 21\sqrt{3}$

Option 2: $21: 22\sqrt{3}$

Option 3: $21: 22\sqrt{2}$

Option 4: $22: 21\sqrt{2}$

Question : The mode of the following data is __________.
13, 15, 31, 12, 27, 13, 27, 30, 27, 28 and 16

Option 1: 28

Option 2: 27

Option 3: 30

Option 4: 31

Question : Which of the following is the lowest ratio?

Option 1: 8 : 19

Option 2: 15 : 38

Option 3: 17 : 38

Option 4: 13 : 19

Question :  The value of $1 \frac{3}{4}+1 \frac{5}{7} \div 2 \frac{3}{7} \times 2 \frac{3}{7}=$?

Option 1: $1 \frac{11}{28}$

Option 2: $2 \frac{13}{28}$

Option 3: $3 \frac{13}{28}$

Option 4: $4 \frac{23}{28}$