C

1003029205

Level: 
C
In the hospital, 22 boys and 18 girls were born in one month. Babies were listed in the register by their date of birth. Find the probability that there are two boys and three girls in the first five places of the register. The results are rounded to four decimal places.
(222)(183)(405)=0.2865
(222)(183)40!35!=0.0024
222183405=0.0276
(223)(182)40!35!=0.0030

1003029204

Level: 
C
A class consists of 50 students including twins, Mark and Martin. For an exam students are randomly divided into two equally sized subgroups. Find the probability that Mark and Martin will be in the same subgroup. The results are rounded to two decimal places.
(4823)+(4825)(5025)=0.49
(4823)(5025)=0.24
2(4824)(5025)=0.51
(4924)(5025)=0.50