exercise 3.2 class 10 maths
1. Solve the following pair of linear equations by substitution method.
5 = -2 m + 3
2 = – 2m
m = -1 Ans.
3. Form the pair of linear equations for the following problems and find their solution by substitution method.
(i) The difference between two numbers is 26 and one number is three times the other. Find them.
Solution : let the two numbers be x and y where x>y
According to question. x-y = 26. …….. (i)
And x = 3y ………..(ii)
Put (ii) in (i)
3y – y = 26
2y = 26
y = 13
Put y = 13 in (ii)
Therefore x = 3 x 13 = 39
So required numbers are 13 and 39
(ii) The larger of two supplementary angles exceeds the smaller by 18 degrees. Find them.
Solution : let to supplementry angles be x and y. Where x> y . Therefore
x + y = 180 ………….(i)
And. x = y + 18 ………….(ii)
Put equation (ii) in ,(i)
y + 18 + y = 180
2y = 180 – 18
2y = 162
y = 162/2 = 81
Put y = 81 in (ii)
x = 81 + 18 = 99
So required angles are 18⁰ and 99⁰
(iii) The coach of a cricket team buys 7 bats and 6 balls for his Rs 3800. Later, she buys 3 bats and 5 balls for Rs 1750. Find the cost of each bat and each ball.
(iv) The taxi charges in a city consist of a fixed charge together with the charge for the distance covered. For a distance of 10 km, the charge paid is Rs105 and for a journey of 15 km, the charge paid is Rs 155. What are the fix charges and the charge per km? How much does a person have to pay for travelling at a distance of 25 km ?
Let the fixed charges be rupees x and the charge for per kilometre be rupees y.
A.T.Q. x + 10y = 105 ………(i)
And x + 15y = 155 ……….(ii)
So x = 155 – 15y ……….(iii)
Put equation (iii) in (i)
155 – 15y + 10y = 105
– 5y = 105 – 155
-5y = -50
y = 10 and put y = 10 in (ii)
x = 155 – 15 x 10
x = 155 – 150
x = 5
So fixed charges is rupees 5 and the charges per kilometre is Rs 10.
(v) A fraction becomes 9/11, if two is added to both the numerator and the denominator. If, 3 is added to both the numerator and the denominator it becomes 5/6, find the fraction.
Therefore. – y = -9
y = 9 now put y= 9 in (i)
11x – 9 x 9 = – 4
11x = – 4 + 81
11x = 77
x = 7
So required fraction is 7/9
(vi) Five year hence the age of jacob will be three times that of his son. 5 years ago jacob was seven time that of his son. What are their present ages ?
Solution : let present age of Jacob be x years and the present age of the son be y years.
5 years hence
Age of Jacob = ( x + 5) yrs
Age of son = ( y + 5) yrs
A.T.Q. x + 5 = 3 (y + 5)
x +5 = 3y + 15
x – 3y = 10 ………..(i)
5 years ago age of Jacob= ( x -5) yrs
5 years ago age of son = ( y -5) yrs
A.T.Q. x-5 = 7 (y-5)
x -5 = 7y -35
x = 7y – 30 ………..(ii)
Put equation (ii) in (i)
7y -30 – 3y = 10
4y = 40
y = 10. Put y = 10 in (ii)
So x = 7 X 10 – 30
x = 70-30
So x = 40
Hence the present age of Jacob is 40 years and that of son is 10 yrs.
Ncert Solutions Class 10 Maths Exercise 1.1 https://10thmathsguide.com/exercise-11-class-10-maths/
Ncert Solutions Class 10 Maths Exercise 1.2
Ncert Solutions Class 10 Maths Exercise 2.1 https://10thmathsguide.com/exercise-21-class-10-maths/
Ncert Solutions Class 10 Maths Exercise 2.2
Ncert Solutions Class 10 Maths Exercise 3.1 https://10thmathsguide.com/exercise-31-class-10-maths/
Ncert Solutions Class 10 Maths Exercise 3.2 https://10thmathsguide.com/exercise-32-class-10-maths/
Ncert Solutions Class 10 Maths Exercise 3.3 https://10thmathsguide.com/exercise-33-class-10-maths/
Ncert Solutions Class 10 Maths Exercise 4.1 https://10thmathsguide.com/exercise-41-class-10-maths/
Ncert Solutions Class 10 Maths Exercise 4.2 https://10thmathsguide.com/exercise-42-class-10-maths/
Ncert Solutions Class 10 Maths Exercise 4.3 https://10thmathsguide.com/exercise-43-class-10-maths/
10th Maths Guide contains the solutions for all questions and problems available in the textbook.10th Maths Guide cover all the topics present in the book like, Real Numbers, Polynomials,linear equations in two variables,Quadratic Equations, Arithmetic Progression,Triangles, coordinate geometry,Introduction of Trigonometry, Some Applications of Trigonometry, circles ,Area Related to Circles, Surface Areas and Volumes , Statistics and Probability.
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