Question
In a party, the ratio between number of present male and
number of present female is 6:5 respectively. After 3 hours, 30 males join the party and 5 women leave the party. If the final ratio between male to female is 12:7, then find the total number of people initially present in the party.Solution
Let the number of male and female present in the party initially be 6x and 5x respectively.
ATQ,
(6x + 30) /(5x - 5) = (12/7)
Or, 7 X (6x + 30) = 12 X (5x - 5)
So, 42x + 210 = 60x - 60
So, 270 = 18x
So, 'x' = 15
So, required number of people = 6x + 5x = 11 X 15 = 165
Among a set of 4 black balls and 3 white balls, how many selections of 3 balls can be made such that at least 2 of them are black balls?
Which of the following is TRUE for “complementary event or ‘not event’”?
A team of 7 researchers is to be formed from 6 biologists and 4 chemists. Find the number of ways to form the team if it must include at least 5 biologi...
- A school wants to form a committee of 5 students from 6 boys and 4 girls. How many ways can the committee be formed if it must contain at least 3 boys?
A person has 12 friends out of which 7 are relatives. In how many ways can he invite 6 friends such that at least 4 of them are relatives?
How many four-letter words without repetition having exactly two vowels can be formed by using the letters of the word "SEMINAR"?
Using all the letters of the word IMPACT, how many words start with a vowel but end with a consonant?
Nine boys have to stand in a circle. In how many ways they are to be stand on the circumference of circle?
In how many ways can the letters of the word TERRORISTS be arranged by taking 4 letters at a time?
A bag contains 4 violet, 2 grey and 6 black pullovers. 3 pullovers are chosen at random. What is the probability that at least 2 pullovers chosen will b...
Relevant for Exams:
