## Selina Concise Mathematics Class 6 ICSE Solutions Chapter 21 Framing Algebraic Expressions (Including Evaluation)

**Selina Publishers Concise Mathematics Class 6 ICSE Solutions Chapter 21 Framing Algebraic Expressions (Including Evaluation)**

ICSE SolutionsSelina ICSE SolutionsML Aggarwal Solutions

APlusTopper.com provides step by step solutions for Selina Concise ICSE Solutions for Class 6 Mathematics. You can download the Selina Concise Mathematics ICSE Solutions for Class 6 with Free PDF download option. Selina Publishers Concise Mathematics for Class 6 ICSE Solutions all questions are solved and explained by expert mathematic teachers as per ICSE board guidelines.

Selina Class 6 Maths ICSE SolutionsPhysicsChemistryBiologyGeographyHistory & Civics

### Framing Algebraic Expressions Exercise 21 – Selina Concise Mathematics Class 6 ICSE Solutions

**Question 1.**

Write in the form of an algebraic expression :

(i) Perimeter (P) of a rectangle is two times the sum of its length (l) and its breadth (b).

(ii) Perimeter (P) of a square is four times its side.

(iii) Area of a square is square of its side.

(iv) Surface area of a cube is six times the square of its edge.

**Solution:**

(i) Let P be the perimeter and / be the length, and b be the breadth.

P = 2 (l + b)

(ii) Let P be the perimeter and a be the side of the square.

P = 4a

(iii) Let A be the area of the square and a be the sides of the square.

A = (a)^{2}

(iv) Let S be the surface area and a be the edges of the cube.

S = 6a^{2}

**Question 2.**

Express each of the following as an algebraic expression :

(i) The sum of x and y minus m.

(ii) The product of x and y divided by m.

(iii) The subtraction of 5m from 3n and then adding 9p to it.

(iv) The product of 12, x, y and z minus the product of 5, m and n.

(v) Sum of p and 2r – s minus sum of a and 3n + 4x.

**Solution:**

(i) x + y – m

(ii)

(iii) 3n – 5m + 9p

(iv) 12xyz – 5mn

(v) p + 2r – s – (a + 3n + 4x)

**Question 3.**

Construct a formula for the following :

Total wages (₹ W) of a man whose basic wage is (₹ B) for t hours week plus (₹ R) per hour, if he Works a total of T hours.

**Solution:**

Wages for t hours = ₹ B

Wages for overtime = R(T – t)

=> Total wages = Wages for t hours + wages for overtime of (T – t) hours

=> ₹ W = ₹ B + ₹ R (T – t)

**Question 4.**

If x = 4, evaluate :

(i) 3x + 8

(ii) x^{2} – 2x

(iii)

**Solution:**

**Question 5.**

If m – 6, evaluate :

(i) 5m – 6

(ii) 2m^{2} + 3m

(iii) (2m)^{2}

**Solution:**

**Question 6.**

If x = 4, evaluate :

(i) 12x + 7

(ii) 5x^{2} + 4x

(iii)

**Solution:**

**Question 7.**

If m = 2, evaluate :

(i) 16m – 7

(ii) 15m^{2} – 10m

(iii)

**Solution:**

16m – 7

= (16 x 2) – 7

= 32 – 7 = 25

**Question 8.**

If x = 10, evaluate :

(i) 100x + 225

(ii) 6x^{2} – 25x

(iii)

**Solution:**

**Question 9.**

If a = – 10, evaluate :

(i) 5a

(ii) a^{2}

(iii) a^{3}

**Solution:**

(i)5a

= 5 x (-10) = -50

**Question 10.**

If x = – 6, evaluate :

(i) 11x

(ii) 4x^{2}

(iii) 2x^{3}

**Solution:**

**Question 11.**

If m = – 7, evaluate :

(i) 12m

(ii) 2m^{2}

(iii) 2m^{3}

**Solution:**

**Question 12.**

Find the average (A) of four quantities p, q, r and s. If A = 6, p = 3, q = 5 and r = 7 ; find the value of s.

**Solution:**

Given, average of four quantities (A) = 6

and p = 3,q = 5, r = 7 and s = ?

**Question 13.**

If a = 5 and b = 6, evaluate :

(i) 3ab

(ii) 6a^{2}b

(iii) 2b^{2}

**Solution:**

**Question 14.**

If x = 8 and y = 2, evaluate :

(i) 9xy

(ii) 5x^{2}y

(iii) (4y)^{2}

**Solution:**

**Question 15.**

If x = 5 and y = 4, evaluate :

(i) 8xy

(ii) 3x^{2}y

(iii) 3y^{2}

**Solution:**

**Question 16.**

If y = 5 and z = 2, evaluate :

(i) 100yz

(ii) 9y^{2}z

(iii) 5y^{2}

(iv) (5z)^{3}

**Solution:**

**Question 17.**

If x = 2 and y = 10, evaluate :

(i) 30xy

(ii) 50xy^{2}

(iii) (10x)^{2}

(iv) 5y^{2}

**Solution:**

**Question 18.**

If m = 3 and n = 7, evaluate :

(i) 12mn

(ii) 5mn^{2}

(iii) (10m)^{2}

(iv) 4n^{2}

**Solution:**

**Question 19.**

If a = -10, evaluate :

(i) 3a – 2

(ii) a^{2} + 8a

(iii) x a2

**Solution:**

**Question 20.**

If x = -6, evaluate :

(i) 4x – 9

(ii) 3x^{2} + 8x

(iii)

**Solution:**

**Question 21.**

If m = -8, evaluate :

(i) 2m + 21

(ii) m^{2} + 9m

(iii)

**Solution:**

**Question 22.**

If p = -10, evaluate :

(i) 6p + 50

(ii) 3p^{2} – 20p

(iii)

**Solution:**

(i) 6p + 50

= (6 x p) + 50

**Question 23.**

If y = -8, evaluate :

(i) 6y + 53

(ii) y^{2 }+ 12y

(iii)

**Solution:**

**Question 24.**

If x = 2 and 7 = -4, evaluate :

(i) 11xy

(ii) 5x^{2}y

(iii) (5y)^{2}

(iv) 8x^{2}

**Solution:**

**Question 25.**

If m = 9 and n = -2, evaluate

(i) 4mn

(ii) 2m^{2}n

(iii) (2n)^{3}

**Solution:**

**Question 26.**

If m = -8 and n = -2, evaluate :

(i) 12mn

(ii) 3m^{2}n

(iii) (4n)^{2}

**Solution:**

**Question 27.**

If x = -5 and y = -8, evaluate :

(i) 4xy

(ii) 2xy^{2}

(iii) 4x^{2}

(iv) 3y^{2}

**Solution:**

**Question 28.**

Find T, if T = 2a – b, a = 7 and b = 3.

**Solution:**

T = 2a – b, a = 1 and b = 3

Put the value of a = 1, and b = 3 in above equation

T = (2 x 7) -3

T = 14 – 3 = 11

T = 11

**Question 29.**

From the formula B = 2a^{2} – b^{2}, calculate the value of B when a = 3 and b = -1.

**Solution:**

B = 2a^{2} – b^{2}

Put the values of a = 3 and b = -1 in above equation

B = 2 x (3)^{2} – (-1)^{2}

B = 18 – 1

B = 17

Value of B is = 17

**Question 30.**

The wages ₹ W of a man earning ₹ x per hour for t hours are given by the formula W = xt. Find his wages for working 40 hours at a rate of ₹ 39.45 per hour.

**Solution:**

T = 40 hours

x = ₹ 39.45

W = xt = 40 x 39.45

W = ₹ 1578

**Question 31.**

The temperature in Fahrenhiet scale is represented by F and the tempera¬ture in Celsius scale is represented by C. If F = x C + 32, find F when C = 40.

**Solution:**

F = x C + 32

Given, C = 40

F = x 40 + 32 = 9 x 8 + 32

F = 104°

Selina Class 6 Maths ICSE SolutionsPhysicsChemistryBiologyGeographyHistory & Civics

latha says

wanted to download so that it will be easy to read.

Swastik says

Nice website to complete our notes

Manasi says

Thx

Apeksha says

Nice website .I love this I don’t know a answer I got it hear. Formulas to learn.