# NCERT Class 8 Mathematics Solutions: Chapter 2 –Linear Equations in One Variable Exercise 2.4 Part 1

Question: 1 Amina thinks of a number and subtracts from it. She multiples the result by 8. The result now obtained is 3 times the same number she thought of. What is the number?

Let Amina think a Number.

According to the question,

Hence, the number is 4.

Question: 2 A positive numbers is 5 times another number. If 21 is added to both the numbers, then one of the new numbers becomes twice the other new number. What are the numbers?

Let positive number

Another number will be

Another number

Question: 3 Sum of the digits of a two-digit number is 9. When we interchange the digits, it is found that the resulting new number is greater than the original number by 27. What is the two-digit number?

Let the digit at tens place be x then digit at one place will be

Original number =

After interchanging the digits, the new number

Original number

Thus, the number is .

Question: 4 One of the two digits of a two-digit number is three times the other digit. If you interchange the digits of this two-digit number and add the resulting number to the original number, you get 88. What is the original number?

Let the digit at tens place be.

Then digit at ones place will be.

Original two digit number =

After interchanging the digits, the new number =

According to the question,

Original number + New number = 88

Hence, Original number