Chapter 2 Linear Equations in One Variable Ex 2.2 Solutions
Question - 1 : - The base of an isosceles triangle is 4/3 cm. The perimeter of the triangle is┬а┬а┬аcm. What is the length of either of the remaining equal sides?
Answer - 1 : -
Base of isosceles triangle = 4/3 cm
Perimeter of triangle =
┬аimage cm = 62/15Let the length of equal sides of triangle be x.
According to the question,
4/3 + x + x = 62/15 cm
тЗТ 2x = (62/15 тАУ 4/3) cm
тЗТ 2x = (62 тАУ 20)/15 cm
тЗТ 2x = 42/15 cm
тЗТ x = (42/30) ├Ч (┬╜)
тЗТ x = 42/30 cm
тЗТ x = 7/5 cm
The length of either of the remaining equal sides are 7/5 cm.
Question - 2 : - I have a total of тВ╣300 in coins of denomination тВ╣1, тВ╣2 and тВ╣5. The number of тВ╣2 coins is 3 times the number of тВ╣5 coins. The total number of coins is 160. How many coins of each denomination are with me?
Answer - 2 : -
Let the number of тВ╣5 coins be x.
Then,
number тВ╣2 coins = 3x
and, number of тВ╣1 coins = (160 тАУ 4x) Now,
Value of тВ╣5 coins = x ├Ч 5 = 5x
Value of тВ╣2 coins = 3x ├Ч 2 = 6x
Value of тВ╣1 coins = (160 тАУ 4x) ├Ч 1 = (160 тАУ 4x)
According to the question,
5x + 6x + (160 тАУ 4x) = 300
тЗТ 11x + 160 тАУ 4x = 300
тЗТ 7x = 140
тЗТ x = 140/7
тЗТ x = 20
Number of тВ╣5 coins = x = 20
Number of тВ╣2 coins = 3x = 60
Number of тВ╣1 coins = (160 тАУ 4x) = 160 тАУ 80 = 80
Question - 3 : - The organisers of an essay competition decide that a winner in the competition gets a prize of тВ╣100 and a participant who does not win gets a prize of тВ╣25. The total prize money distributed is тВ╣3,000. Find the number of winners, if the total number of participants is 63.
Answer - 3 : -
Let the numbers of winner be x.
Then, the number of participants who didnтАЩt win = 63 тАУ x
Total money given to the winner = x ├Ч 100 = 100x
Total money given to participant who didnтАЩt win = 25├Ч(63-x)
According to the question,
100x + 25├Ч(63-x) = 3,000
тЗТ 100x + 1575 тАУ 25x = 3,000
тЗТ 75x = 3,000 тАУ 1575
тЗТ 75x = 1425
тЗТ x = 1425/75
тЗТ x = 19
Therefore, the numbers of winners are 19.
Question - 4 : - If you subtract 1/2 from a number and multiply the result by 1/2, you get 1/8 what is the number?
Answer - 4 : -
Let the number be x.
According to the question,
(x тАУ 1/2) ├Ч ┬╜ = 1/8
x/2 тАУ ┬╝ = 1/8
x/2 = 1/8 + ┬╝
x/2 = 1/8 + 2/8
x/2 = (1+ 2)/8
x/2 = 3/8
x = (3/8) ├Ч 2
x = ┬╛
Question - 5 : - The perimeter of a rectangular swimming pool is 154 m. Its length is 2 m more than twice its breadth. What are the length and the breadth of the pool?
Answer - 5 : -
Given that,
Perimeter of rectangular swimming pool = 154 m Let the breadth of rectangle be = x
According to the question,
Length of the rectangle = 2x + 2 We know that,
Perimeter = 2(length + breadth)
тЗТ 2(2x + 2 + x) = 154 m
тЗТ 2(3x + 2) = 154
тЗТ 3x +2 = 154/2
тЗТ 3x = 77 тАУ 2
тЗТ 3x = 75
тЗТ x = 75/3
тЗТ x = 25 m
Therefore, Breadth = x = 25 cm
Length = 2x + 2
= (2 ├Ч 25) + 2
= 50 + 2
= 52 m
Question - 6 : - Sum of two numbers is 95. If one exceeds the other by 15, find the numbers.
Answer - 6 : -
Let one of the numbers be= x.
Then, the other number becomes x + 15 According to the question,
x + x + 15 = 95
тЗТ 2x + 15 = 95
тЗТ 2x = 95 тАУ 15
тЗТ 2x = 80
тЗТ x = 80/2
тЗТ x = 40
First number = x = 40
And, other number = x + 15 = 40 + 15 = 55
Question - 7 : - Two numbers are in the ratio 5:3. If they differ by 18, what are the numbers?
Answer - 7 : -
Let the two numbers be 5x and 3x. According to the question,
5x тАУ 3x = 18
тЗТ 2x = 18
тЗТ x = 18/2
тЗТ x = 19
Thus,
The numbers are 5x = 5 ├Ч 9 = 45
And 3x = 3 ├Ч 9 = 27.
Question - 8 : - Three consecutive integers add up to 51. What are these integers?
Answer - 8 : -
Let the three consecutive integers be x, x+1 and x+2. According to the question,
x + (x+1) + (x+2) = 51
тЗТ 3x + 3 = 51
тЗТ 3x = 51 тАУ 3
тЗТ 3x = 48
тЗТ x = 48/3
тЗТ x = 16
Thus, the integers are
x = 16
x + 1 = 17
x + 2 = 18
Question - 9 : - The sum of three consecutive multiples of 8 is 888. Find the multiples.
Answer - 9 : -
Let the three consecutive multiples of 8 be 8x, 8(x+1) and 8(x+2). According to the question,
8x + 8(x+1) + 8(x+2) = 888
тЗТ 8 (x + x+1 + x+2) = 888 (Taking 8 as common)
тЗТ 8 (3x + 3) = 888
тЗТ 3x + 3 = 888/8
тЗТ 3x + 3 = 111
тЗТ 3x = 111 тАУ 3
тЗТ 3x = 108
тЗТ x = 108/3
тЗТ x = 36
Thus, the three consecutive multiples of 8 are:
8x = 8 ├Ч 36 = 288
8(x + 1) = 8 ├Ч (36 + 1) = 8 ├Ч 37 = 296
8(x + 2) = 8 ├Ч (36 + 2) = 8 ├Ч 38 = 304
Question - 10 : - Three consecutive integers are such that when they are taken in increasing order and multiplied by 2, 3 and 4 respectively, they add up to 74. Find these numbers.
Answer - 10 : -
Let the three consecutive integers are x, x+1 and x+2. According to the question,
2x + 3(x+1) + 4(x+2) = 74
тЗТ 2x + 3x +3 + 4x + 8 = 74
тЗТ 9x + 11 = 74
тЗТ 9x = 74 тАУ 11
тЗТ 9x = 63
тЗТ x = 63/9
тЗТ x = 7
Thus, the numbers are:
x = 7
x + 1 = 8
x + 2 = 9