# Class - boys and girls

In the class are 60% boys and 40% girls. Long hair has 10% boys and 80% girls.

a) What is the probability that a randomly chosen person has long hair?
b) The selected person has long hair. What is the probability that it is a girl?

p1 =  0.38
p2 =  0.8421

### Step-by-step explanation:

${p}_{1}=0.1\cdot 0.6+0.8\cdot 0.4=0.38$
${p}_{2}=0.8\cdot 0.4\mathrm{/}{p}_{1}=0.8421$

We will be pleased if You send us any improvements to this math problem. Thank you!

Tips to related online calculators
Would you like to compute count of combinations?

## Related math problems and questions:

• Classroom
There are eighty more girls in the class than boys. Boys are 40 percent and girls are 60 percent. How many are boys and how many girls?
• Utopia Island
A probability of disease A on the island of Utopia is 40%. A probability of occurrence among the men of this island, which make up 60% of all the population (the rest are women), is 50%. What is the probability of occurrence of A disease among women on Ut
• Family
What is the probability that a family with 7 childrens have: exactly 5 girls? 7 girls and 0 boys? Consider the birth probability of a girl is 48.69% and boy 51.31%.
• Family
94 boys are born per 100 girls. Determine the probability that there are two boys in a randomly selected family with three children.
• The university
At a certain university, 25% of students are in the business faculty. Of the students in the business faculty, 66% are males. However, only 52% of all students at the university are male. a. What is the probability that a student selected at random in the
• Boys and girls
There are eight boys and nine girls in the class. There were six children on the trip from this class. What is the probability that left a) only boys b) just two boys
• Bulbs
In the box are 6 bulbs with power 75 W, 14 bulbs with power 40 W and 15 with 60 W. Calculate probability that a randomly selected bulb is:
• Alarm systems
What is the probability that at least one alarm system will signal the theft of a motor vehicle when the efficiency of the first system is 90% and of the independent second system 80%?
• The box
The box contains three light bulbs with a wattage of 40 W and two pieces of light bulbs with a wattage of 60 W. What is the probability of the event that two randomly selected light bulbs will both be 40 W?
• Alcohol mixing
How much 55% alcohol we must pour into 1500 g 80% alcohol to form a 60% alcohol? How much 60% alcohol created?
• Shooters
In army regiment are six shooters. The first shooter target hit with a probability of 49%, next with 75%, 41%, 20%, 34%, 63%. Calculate the probability of target hit when shooting all at once.
• Standard deviation
Find standard deviation for dataset (grouped data): Age (years) No. Of Persons 0-10 15 10-20 15 20-30 23 30-40 22 40-50 25 50-60 10 60-70 5 70-80 10
• Created trio
What is the probability that in the created trio, which consists of 19 boys and 12 girls, they will be: a) the boys themselves b) the girls themselves c) 2 boys and 1 girl?
• Final exam
There are 5 learners in a class that has written a final exam Aleta scored 55% vera scored 36% and Sibusiso scored 88% if Thoko scored 71% and the class average was 63%. What was Davids score as a percentage?
• Competition
15 boys and 10 girls are in the class. On school competition of them is selected 6-member team composed of 4 boys and 2 girls. How many ways can we select students?
• Class
In 7.C clss are 10 girls and 20 boys. Yesterday was missing 20% of girls and 50% boys. What percentage of students missing?
• Double probability
The probability of success of the planned action is 60%. What is the probability that we will achieve success at least once if this action is repeated twice?