Advertisements
Advertisements
प्रश्न
A teacher wants to select the class monitor in a class of 30 boys and 20 girls. In how many ways can the monitor be selected if the monitor must be a girl or a boy?
Advertisements
उत्तर
There are 30 boys and 20 girls.
A teacher can select any boy as a class monitor from 30 boys in 30 different ways and he can select any girl as a class monitor from 20 girls in 20 different ways.
∴ by the fundamental principle of addition, the total number of ways a teacher can select a class monitor
= 30 + 20 = 50
Hence, there are 50 different ways to select a class monitor.
APPEARS IN
संबंधित प्रश्न
Given 5 flags of different colours, how many different signals can be generated if each signal requires the use of 2 flags, one below the other?
How many two letter words can be formed using letters from the word SPACE, when repetition of letters is allowed?
How many numbers between 100 and 1000 have 4 in the units place?
How many numbers between 100 and 1000 have the digit 7 exactly once?
How many three-digit numbers can be formed using the digits 2, 3, 4, 5, 6 if digits can be repeated?
In a test, 5 questions are of the form 'state, true or false'. No student has got all answers correct. Also, the answer of every student is different. Find the number of students appeared for the test.
How many numbers between 100 and 1000 have 4 in the units place?
A school has three gates and four staircases from the first floor to the second floor. How many ways does a student have to go from outside the school to his classroom on the second floor?
How many words can be formed by writing letters in the word CROWN in different order?
Answer the following:
A hall has 12 lamps and every lamp can be switched on independently. Find the number of ways of illuminating the hall.
A person went to a restaurant for dinner. In the menu card, the person saw 10 Indian and 7 Chinese food items. In how many ways the person can select either an Indian or a Chinese food?
In how many ways 5 persons can be seated in a row?
Four children are running a race:
In how many ways can the first two places be filled?
Count the number of three-digit numbers which can be formed from the digits 2, 4, 6, 8 if repetitions of digits is not allowed
How many three-digit numbers are there with 3 in the unit place?
with repetition
How many three-digit odd numbers can be formed by using the digits 0, 1, 2, 3, 4, 5? if the repetition of digits is not allowed
Count the numbers between 999 and 10000 subject to the condition that there are no restriction
How many three-digit numbers, which are divisible by 5, can be formed using the digits 0, 1, 2, 3, 4, 5 if repetition of digits are not allowed?
How many three-digit numbers, which are divisible by 5, can be formed using the digits 0, 1, 2, 3, 4, 5 if repetition of digits are allowed?
How many numbers are there between 1 and 1000 (both inclusive) which are divisible neither by 2 nor by 5?
How many strings can be formed using the letters of the word LOTUS if the word either starts with L or ends with S?
How many strings can be formed using the letters of the word LOTUS if the word neither starts with L nor ends with S?
In how many ways 10 pigeons can be placed in 3 different pigeon holes?
Find the number of ways of distributing 12 distinct prizes to 10 students?
Find the value of 3! – 2!
Find the value of 3! × 2!
Evaluate `("n"!)/("r"!("n" - "r")!)` when n = 6, r = 2
Evaluate `("n"!)/("r"!("n" - "r")!)` when n = 10, r = 3
Find the value of n if `1/(8!) + 1/(9!) = "n"/(10!)`
Choose the correct alternative:
The number of five digit telephone numbers having at least one of their digits repeated i
Choose the correct alternative:
There are 10 points in a plane and 4 of them are collinear. The number of straight lines joining any two points is
All the letters of the word PADMAPRIYA are placed at random in a row. The probability that the word PRIY A occurs without getting split is ______
How many numbers are there between 99 and 1000 having atleast one of their digits 7?
Eight chairs are numbered 1 to 8. Two women and 3 men wish to occupy one chair each. First the women choose the chairs from amongst the chairs 1 to 4 and then men select from the remaining chairs. Find the total number of possible arrangements.
Three letters can be posted in five letterboxes in 35 ways.
In a steamer there are stalls for 12 animals, and there are horses, cows and calves (not less than 12 each) ready to be shipped. They can be loaded in 312 ways.
If the number of five-digit numbers with distinct digits and 2 at the 10th place is 336 k, then k is equal to ______.
