Exercise 7 B
Q1 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 1
The sum of Ritu age and Ashu age is 25. Ritu is 12 years old . Write an equation to find ashu age ?
Sol: Let Ritu age =x ; Ashu age = y
Acc. to question = x+y=25
= $12+y=25 \Rightarrow y=25-12=13$
Ashu age = 13 year
Q2 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 2
A number decreased by 4 is equal to -6 . find the number
Sol: Let the number =x
Acc. to question x-4=-6
$ \Rightarrow x=-6+4 \Rightarrow x=-2$
The number =- 2 Ans
Q3 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 3
7 times a number decreased by 3 equal to 18. find the number
Sol :
Let the number= x
$\Rightarrow 7 \times x-3=18 $
$\Rightarrow 7 x=18+3$
$\Rightarrow 7 \times x=21 $
$\Rightarrow x=\frac{21}{7} \Rightarrow x=3$
Q4 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 4
One- fifth of a number is 9. find the number
Sol :
Let the number =x
Acc. to question = $\frac{1}{5} \times x=9$
$x=9 \times 5 \quad \Rightarrow x=45$
Q5 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 5
How old is ramesh if 10 year ago he was 25 year old ?
Sol :
Age of ramesh 10 year ago = 25 year
∵ Age of ramesh , after 10 year = 25 + 10 = 35 year
Q6 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 6
Apporv received three-fourths of all votes cast in the election far school president. If he received 876 votes, how many student voted ?
Sol :
Apoorv received votes = 876
Let total number of votes = x
Acc. to question = $\frac{3}{4} \times x=876$
x= $876 \times \frac{4}{3}=1168$
Total No, of votes = 1168 votes of students
Q7 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 7
After gaining 15 kg , Nisha weight 60 kg . What was her previous weight ?
Sol: Let the previous weight of Nisha = x
Weight gained = 15kg
x+ 15 =60 = x= 60 -15 =45kg
Previous weight = 45kg answer
Q8 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 8
A pole x meters long is broken into two parts, One part is 5 meters long.
(i) What is the length of the other parts?
(ii) If the other part is 6 meters long. write an equation and use it to find the value of x
Sol: (i) Length of pole = x m
other part = (x-5) m answer
(ii) If the other part = x-5
Acc , to Question = x -5 = 6
=x=6+5 = 11m
Length of pole = 11m answer
Q9 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 9
The teacher tells the class that the highest marks obtained by a student in her class in three times the lowest marks minus seven . If the highest marks are 86 , find the lowest marks.
Sol: Let the lowest marks = x
Acc. to question= $3 x-7=86 \Rightarrow 3 x=86+7 .$
$3 x=93 \Rightarrow x=\frac{93}{3}=31$
∵ Lowest marks = 31
Q10 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 10
Benny thinks of a number subtracts 18 from it and divides the difference by 3. The result is -4 . what is the number ?
Sol: Let the number =x
$\frac{x-18}{3}=-4 \Rightarrow x-18=-4 \times 3$
$\Rightarrow \quad x-18=-12 \quad x=-12+18$
$\Rightarrow \quad x=6 \quad$ Numbcr $=6$ answer
Q11 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 11
Mr. Grover is three times as old as his son and the sum of their age is 48 . How old is each ?
Sol: Let the age of son = x
Age of Mr. Grover= 3x
$\Rightarrow \quad 3 x+x=48 \Rightarrow 4 x=48 .$
$\Rightarrow \quad x=\frac{48}{4}=12$ years $\therefore$ Son age = 12 years answer
= Mr. Grover age $=3 \times 12=36$ years
Q12 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 12
Sunil is 48 years old . He is 7 years less than 5 times his daughter's age . What is his daughter's age ?
Sol: Let daughter age =x
$\Rightarrow 5 x-7=48 \Rightarrow 5 x=48+7 \Rightarrow 5 x=55$
$\Rightarrow x=\frac{55}{5} \Rightarrow x=11$ years
daughter's age = 11 y answer
Q13 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 13
A number is 6 more than two times another number. The sum of tthe two number is 24. Find the number
Sol: Let one number =x ; Other = y = 2x +6
$x+y=24 \Rightarrow x+2 x+6=24$
$3 x=24-6 \quad \Rightarrow \quad 3 x=18 \quad \Rightarrow x=\frac{18}{3}=6$
x =6 ; y = 2x +6 = $2 \times 6+6=12+6=18$
y = 18 answer
Q14 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 14
Four times Sonu age decrease by 3 is equal to 3 times his age increased by 7. How old is sonu?
Sol :
Sonu age =x
$\Rightarrow 4 x-3=3 x+7$
$\Rightarrow 4 x-3 x=7+3$
$\Rightarrow x=10$ years
Q15 | Ex-7B | Class 7 | SChand Composite Maths | Linear Equation with one Variable | myhelper
Question 15
Find the 3 Consecutive number whose sum is 81
Sol :
Number are x, x+1 , x+2
$x+x+1+x+2=81$
3x+3=81
$3 x=81-3$
$3 x=78 \Rightarrow x=\frac{78}{3}$
x=26
x +1 = 26+ 1 = 27
x+2 =26+ 2 = 28 answer
No comments:
Post a Comment