The document RD Sharma Solutions - Chapter 1 - Rational Numbers (Ex -1. 7), Class 8, Maths Class 8 Notes | EduRev is a part of the Class 8 Course RD Sharma Solutions for Class 8 Mathematics.

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**Question 1: Divide:**

**(i) 1 by 1/2****(ii) 5 by âˆ’5/7(iii) âˆ’3/4 by 9/âˆ’16****(iv) âˆ’7/8 by âˆ’21/16****(v) 7/âˆ’4 by 63/64****(vi) 0 by âˆ’7/5****(vii) âˆ’3/4 by âˆ’6****(viii) 2/3 by âˆ’7/12****(ix) âˆ’4 by âˆ’3/5****(x) âˆ’3/13 by âˆ’4/65**

**Answer :**

**Question 2: Find the value and expre****ss as a rational number in standard form:**

**Answer 2:**

**Question 3: The product of two rational numbers is 15. If one of the numbers is âˆ’10, find the other.****Answer 3:**

Let the other number be x.

âˆ´ xÃ—(âˆ’10)=15** **

So, the other number is -3/2.**Question 4: The product of two rational numbers is -8/9. If one of the numbers is -4/15, find the other.**

**Answer 4:** Let the other number be x.

or x= 10/3

Thus, the other number is 10/3.**Question 5: By what number should we multiply -1/6-16 so that the product may be -23/9?****Answer 5: **Let the number be x.

Therefore, the other number is 46/3.

**Question 6: By what number should we multiply -15/28-1528 so that the product may be -5/7?-57?**

**Answer 6:** Let the other number be x.

or x= 4/3

Thus, the other number is 4/3.**Question 7: By what number should we multiply -8/13 so that the product may be 24?**

**Answer 7:** Let the number be x.

**or x=âˆ’39 **

Thus, the number is âˆ’39.**Question 8: By what number should -3/434 be multiplied in order to produce 2/3?23?****Answer 8: **Let the other number that should be multiplied with -3/4 to produce2/3 be x.

Thus, the number is -8/9.

**Question 9: Find (x + y) Ã· (x âˆ’ y), if**

**Answer 9:**

**Question 10: The cost of metres of rope is Rs . Find its cost per metre.**

**Answer 10: **The cost of metres of rope is Rs .**âˆ´Cost per metre = **

= 153/92

**Question 11: The cost of metres of cloth is Rs Find the cost of cloth per metre.****Answer 11: ** The cost of metres of cloth is Rs.

âˆ´ Cost per metre

=

= 129/4

Thus, or Rs 32.25 is the cost of cloth per metre. **Question 12: By what number should -33/16 be divided to get -11/4?****Answer 12:** Let the number be x.

Thus, the number is 3/4.

**Question 13: Divide the sum of -13/5-135 and 12/7127 by the product of -31/7 and -1/2.-317 and -12.**

**Answer 13:**

**=** -2/5

**Question 14: Divide the sum of 65/12 and 12/7 by their difference.**

**Answer 14:**

= 599/311**Question 15: If 24 trousers of equal size can be prepared in 54 metres of cloth, what length of cloth is required for each trouser?**

**Answer 15:** Cloth needed to prepare 24 trousers=54 m

âˆ´ Length of the cloth required for each trousers= 54Ã·24= 54/24 = 9/4 m = metres