# NCTB Class 6 Math Chapter Five Exercise 5 Solution

NCTB Class 6 Math Chapter Five Exercise 5 Solution by Math Expert. Bangladesh Board Class 6 Math Solution Chapter 5 “Simple Equations” Exercise 5 Solution.

 Board NCTB Class 6 Subject Mathematics Chapter 5 Chapter Name “Simple Equations” Exercise 5 Solution

### Exercise:- 5

(1) Which one of the following is the value of the variable in the equation x+3=8?

Solution:-

X+3= 8

=> x= 8-= 5

Therefore, value of x =5

(2) Which one of the following is the root of the equation 4x=8?

Solution:-

Equation, 4x=8

=> x= 8/4

= 2

(3) Amount of Mack’s money is twice the amount of Marrie’s money. They have together 30 taka in total. How much money does Marrie have ?

Solution:-

Let, Marrrie’s money = x Rs

Mack’s money – 2x Rs

Therefore, x+2x = 30

=> 3x = 30

=> x = 30/3

= 10

Therefore, Marrie have (d) 10 Rs.

(4) What is the peremeter of a rectangular garden having length of x metre and breadth of y metre?

Solution:-

Perimeter of a rectangular garden = 2 (x +y)m.

(5) Find out the value of x when 3 is added to twice x that gives a sum of 9.

Solution:-

2x +3 = 9

=> 2x = 9-3

=> x= 6/2

= 3

(6) In the equation 6x+3=9

Solution:-

6x +3 = 9

=> 6x= 6

=> x=6/6

= 1

Correct is (a) (i) and (ii)

(7) If a, b, c refer to any number and a=b

Solution:-

A, b, c refer to any number and a=b

Therefore, (d) (i), (ii), (iii) are correct.

(8) What is the ratio of greater and smaller number?

Solution:-

The ratio of greater and smaller number is—(d) 4:1

Let smaller= x; greater= 4x

4x-x = 30                                  Therefore, = 4×10

=> x= 30/3                                                    = 40.

= 10

(9) What is the smaller number?

Solution:-

Smaller number is = 10 (b).

(10) Bimal bought an exercise book and a pencil for 30 taka from a shop. The pencil costa x taka and exercise book cots twice the cost of the pencil. Look at the following data:

Solution:-

Therefore, x+2x = 30

=> 3x= 30

=> x= 10Rs

Pencil cost 10Rs ; Exercise book cost = 2×10

= 20 Rs

(d) (i), (ii), (iii)

(11) Sum of two natural numbers is 24. Then,

(1) If one number is 8, which one of the following is the other number?

Solution:-

Other number is = 24-8

= 16

(2) Twice of which of the following numbers is added to 6, the sum well be the same?

Solution:-

[6+6=12]

Solve the following questions (12-32):

(12) Solution:-

X+4 = 13

=> x = 13-4 = 9

(13) Solution:-

X+5 = 9

=> x = 9-5

= 4

(14) Solution:-

Y+1 = 10

=> y = 10-1

9

(15) Solution:

Y- 5 = 11

=> y = 11+

= 16

(16) Solution:-

Z +3 = 15

=> z =15-3

= 12

(17) Solution:-

3x = 12

=> x = 12/3

= 4

(18) Solution:-

2x +1 = 9

=> 2x = 9-1

=> x = 8/2

= 4

(19) Solution:-

4x-5 = 11

=> 4x = 11+5

=> x = 16/4

= 4

(20) Solution:-

3x-5 = 17

=> 3x = 17+5

=> x = 22/3

(21) Solution:-

7x-2 = x+16

=> 7x-x = 16+2

= 6x = 18

=> 18/6

= 3

(22) Solution:-

3-x = 14

=> -x = 14-3

=> -x = 11

=> x = -11

(23) Solution:-

2x +9 = 3

=> 2x = 3-9

=> x =-6/2

= -3

Solve by forming equation (24-35):

(24) If 6 is added to twice a number, the sum will be 14. What is the number?

Solution:-

Let, number is = x

Therefore, 2x +6 = 14

=> 2x = 14-6

=> x = 8/2

= 4

(25) If 5 is subtracted from a number, the difference will be 11. What is the number?

Solution:-

Let, number is x.

x- 5 = 11

x- 5 = 11

=> x= 11

= 16

(26) What is the number whose 7 times will be equal to 21?

Solution:-

Let, number = x.

Therefore, xX7 = 21

=> 7x = 21

=> x = 21/7

= 3

(27) If 3 times number is added to 4 times a number, the sum will be 23. What is the number?

Solution:-

Let, number = x.

Therefore, 4x =3 = 23

=> 4x = 20

=> x = 20/4

= 5

(28) If 3 times number is added to 5 times that number, the sum will be 32. Find the number.

Solution:-

Let, number = x.

3x+ 5x = 32

=> 8x = 32

=> x= 32/8

= 4

(29) If twice of a number is subtracted from four times the number, the difference will be 24. Find the number.

Solution:-

Let, the number = x.

4x-2x = 24

=> x= 24/2

= 12

The number is 12.

(30)  If the price of a pen is less than is specified price by 2 taka, the price would be 10 taka. What is the price of the pen?

Solution:-

Let, price of the pen = x Rs.

x- 2 = 10

=> x= 10+2

= 12Rs

(31) Monika has 4 times more chocolates than Kanika. They have 25 chocolates together. How many chocolates does Kanika have?

Solution:-

Let, Kanika have = x chocolates

X+4x = 25

=> 5x = 25

=> x = 25/5

X=5

Therefore, Kanika have 5 chocolates.

(32) The sum of two consecutive even natural numbers is 30. Find the numbers.

Solution:-

Therefore, x+x+2= 30

=> 2x = 30-2

=> x = 28/2

= 14

One number is  = 14 and another number is = (14+2) = 16

(33) The sum of three consecutive odd natural numbers is 27. Find the numbers.

Solution:-

Let, three consecutive odd natural numbers x, x+2, x+4

Therefore, x+x+2+x+y = 27

=> 3x = 27-6

=> x = 21/3

X = 7

Therefore, Three numbers are = 7, (7+2) = 9, (9+2) = 11

(34) The Length of a rectangular flower garden is 2 metre more than its breadth.

Solution:-

Let, the breadth of garden = x.

Length = (x+2)

(a) If the breadth of the garden is x metre, find its perimeter in terms of x.

Solution:-

Perimeter

Therefore, 2 (x+2+x)

=> 2 (2x+2)

=> (4x+4)m

(b) If the perimeter of the garden is 36 metre, what will be the cost to clean per square metre?

Solution:-

2 (x+2+x) = 36

=> 2 (2x+2) = 36

=> 4x+ 4 = 36

=> 4x = 36-4

X = 32/4

Therefore Length = (8+2) = 10m.

Area = (10×8) = 80sqm.

(c) It cost 320 taka to clean the garden. What will be the cost to clean per square metre?

Solution:-

To clean per square meter cost = 320/80 taka

= 4 TK.

(35) The sum of three consecutive natural numbers is 24.

(a) If the smallest number is x, write down the other two numbers in terms of x.

Solution:-

The other two numbers are x+1, x+2

(b) From the given facts, determine the three numbers.

Solution:-

X+ x+1 +x+2 = 24

=> 3x = 24-3

=> x= 21/3

=7

Three numbers are, 7, 8, 9.

Updated: December 5, 2020 — 9:14 am