NCERT solutions for Computer Science [English] Class 11 chapter 4 - Introduction to Problem Solving [Latest edition]

Write a pseudocode that reads two numbers and divides one by another and displays the quotient.

Two friends decide who gets the last slice of a cake by flipping a coin five times. The first person to win three flips wins the cake. An input of 1 means player 1 wins a flip, and a 2 means player 2 wins a flip. Design an algorithm to determine who takes the cake.

Write the pseudocode to print all multiples of 5 between 10 and 25 (including both 10 and 25).

Give an example of a loop that is to be executed a certain number of times.

Suppose you are collecting money for something. You need ₹ 200 in all. You ask your parents, uncles, and aunts as well as grandparents. Different people may give either ₹ 10, ₹ 20, or even ₹ 50. You will collect till the total becomes 200. Write the algorithm.

Write the pseudocode to print the bill depending on the price and quantity of an item. Also print Bill GST, which is the bill after adding 5% of the tax to the total bill.

Write pseudocode that will perform the following:

1. Read the marks of three subjects: Computer Science, Mathematics, and Physics, out of 100.
2. Calculate the aggregate marks.
3. Calculate the percentage of marks.

Write an algorithm to find the greatest among two different numbers entered by the user.

Write an algorithm that performs the following:

Ask a user to enter a number. If the number is between 5 and 15, write the word GREEN. If the number is between 15 and 25, write the word BLUE. if the number is between 25 and 35, write the word ORANGE. If it is any other number, write that ALL COLOURS ARE BEAUTIFUL.

Write an algorithm that accepts four numbers as input and finds the largest and smallest of them.

Write an algorithm to display the total water bill charges of the month depending upon the number of units consumed by the customer as per the following criteria:

• for the first 100 units @ 5 per unit
• for next 150 units @ 10 per unit
• more than 250 units @ 20 per unit

Also, add meter charges of 75 per month to calculate the total water bill.

What are conditionals? When they are required in a program?

Match the pairs.

Flowchart Symbol	Functions
	Flow of Control
	Process Step
	Start/Stop of the Process
	Data
	Decision Making

Following is an algorithm for going to school or college. Can you suggest improvements in this to include other options?

Reach_School_Algorithm

1. Wake up
2. Get ready
3. Take lunch box
4. Take the bus
5. Get off the bus
6. Reach school or college

Write pseudocode to calculate the factorial of a number (Hint: Factorial of 5, written as 5! = 5 × 4 × 3 × 2 × 1).

Draw a flowchart to check whether a given number is an Armstrong number. An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 371 is an Armstrong number since 3**3 + 7**3 + 1**3 = 371.

Following is an algorithm to classify numbers as “Single Digit”, “Double Digit” or “Big”.

Classify_Numbers_Algo
INPUT Number
IF Number < 9
             "Single Digit"
Else If Number < 99
             "Double Digit"
Else
             "Big"

Verify for (5, 9, 47, 99, 100, 200) and correct the algorithm if required.

For some calculations, we want an algorithm that accepts only positive integers up to 100.

Accept_1 to 100_Algo
INPUT Number
IF (0 <= Number) AND (Number <= 100)
       ACCEPT
Else
       REJECT

1. On what values will this algorithm fail?
2. Can you improve the algorithm?