NCTB Class 7 Math Chapter Seven Exercise 7.2 Solution by Math Expert. Bangladesh Board Class 7 Math Solution Chapter 7.2“Simple Equations” Exercise 7.1 Solution.
|
Board |
NCTB |
| Class |
7 |
|
Subject |
Math |
| Chapter |
Seven |
|
Chapter Name |
“Simple Equations” |
| Exercise |
7.2 Solution |
Exercise: 7.2
(1) Solution:- Let, the number is = x
Therefore, 2x +5 = 25
=> 2x= 25-5
=> x= 20/2
= 10 Therefore, The number is 10.
(2) Solution:- Let, the number ix ‘x’
Therefore, x- 27= -21
=> x-27= -21
=> x= -21+27
= 6
Therefore, Number is 6.
(3) Solution:- Let, the number is ‘x’
Therefore, x/3 = 4
=> x= 12
Therefore, The number is 12.
(4) Solution:- Let, the number is ‘x’
Therefore, (x-5) x5 = 20
=> 5x- 25 – 20
=> 5x-25 = 20
=> 5x = 20+25
=> x= 45/5
= 9
Therefore, Number is 9.
(5) Solution:- Let, the number is = x
Therefore, x/2 – x/3 = 6
=> 3x -2x/6 = 6
=> x= 36
Therefore, the number is 36.
(6) Solution:- Let, the numbers are, x, x+1, x+2
Therefore, x+x+1x+2 = 63
=> 3x = 63-3
=> x= 60/3
= 20
Therefore, 1st number is = 20
2nd, number is = 20+1= 21
3rd number is = 20+2= 22
(7) Solution:- Let, the smaller no. is = x
Bigger No. is = (55-x)
Therefore, 5(55-x) = 6x
=> 275-5x= 6x
=> 11x= 275
=> x= 275/11
= 25
Therefore, smaller number is = 25
Bigger number is = (55-25)
= 30.
(8) Solution:- Let, Rita has x Rs.
Gita has (x-6) TK.
Mita has (x+12) TK.
Therefore, x +x-6+x +12 = 180
=> 3x +6= 180
=> 3x= 180-6
=> x= 174/3
= 58 TK.
Therefore, Rita has 58TK.
Gita has (58-6) = 48 TK.
Mita has (58+12) = 70TK.
(9) Solution:- Let, the price of khata= x TK.
Therefore, price of pen = (75-x) TK.
Therefore, x-5= 2(75-x+2)
=> x-5 = 2(77-x)
=> x-5= 154-2x
=> x-5 = 154-2x
=> x+2x= 154+5
=> x= 159/3
= 53
Therefore, price of khata 53TK.
Therefore, price of pen (75-53)TK.
= 22TK.
(10) Solution:- Let, the total No. of fret = x
Therefore, Apple = x X ½ = x/2
Orange = x X1/3 = x/3
Orange= 40piece
Therefore, x/2 + x/3 +40= x
=> 3x+2x+240/6 = x
=> 5x+240 = 6x
=> x= 240
Therefore, Total No. 240.
(11) Solution:- Let, the age of son = x yr.
Father’s present age = 6x yr.
Therefore, 5yrs later,
Age of son = (x+5) yr.
11 of father = (6x+5) yr.
Therefore, (x+5) + (6x+5) = 45
=> 7x+10 = 45
=> 7x = 45-10
=> x= 35/7
= 5
Therefore, son’s present age 5yr.
Father present age = (5×6) = 30yr.
(12) Solution:- Liza: sikha age = 2:3
Therefore, Let, age = 2x & sikha’s age = 3x yr.
Therefore, 2x+3x= 30
=> 5x= 30
=> x= 30/5
= 6yr.
Therefore, Liza’s age = 2×6 = 12yr.
Sikha’s age= 3×6 = 18 yr.
(13) Solution:- Let, suman’s run = x
And, Iman’s man = 2x-5
Therefore, x+2x-5 = 58
=> 3x= 58+5
=> x= 63/3
=> 21
Iman’s run = (21×2-5)
= 37.
(14) Solution:- Let, the distance = ‘x’ km.
10min = 10/60
= 1/6
Therefore, to cover x km in 30km/hr take time x/30hr,
And, to cover 25km taking time x/25hr.
Therefore, x/25 – x/30 = 1/6
=> 6x-5x/150= 1/6
=> x = 150/6
= 25km.
(15) Solution:- Let, the breadth= ‘x’ m
Length= 3x m
Therefore, 2(x+3x) = 40
=> 8x= 40
=> x= 40/8
= 5m
Therefore, Breadth is = 5m
Length is = (3×5) = 15m.
