Decimal Fraction problems
- 1. If the numerator of a fraction is increased by 2 and the denominator is increased by 1, the fraction because 5/8 and if the numerator of the same fraction is increased by 3 and the denominator is increased by 1, the fraction becomes 3/4 . What is the original fraction?
Options- A. Data inadequate
- B. 2/7
- C. 4/7
- D. 3/7 Discuss
Correct Answer: 3/7
Explanation:
Let the original fraction be p/q
Then, (p + 2) / (q + 1) = 5/8
? 8p - 5q = 11 .....(i)
Again (p + 3) / (q + 1) = 3/4
? 4p - 3q = 9 ...(ii)
Solving equations , (i) and (ii), we get ,
p = 3 and q = 7
? Fraction = 3/7
- 2. If the numerator of a fraction is increased by 2 and denominator is increased by 3, the faction becomes 7/9 and if numerator as well as denominator are decreased by 1, the fraction becomes 4/5. What is the original fraction?
Options- A. 13/16
- B. 9/11
- C. 5/6
- D. 17/21 Discuss
Correct Answer: 5/6
Explanation:
Let the numerator and denominator be p and q respectively.
Then, (p + 2) / (q + 3) = 7/9
? 9(p + 2) = 7(q +3)
? 9p - 7q = 3 ....(i)
Again, (p - 1) / (q - 1) = 4/5
? 5p - 4q = 1 ....(ii)
Solving (i) and (ii) we get,
p = 5, q = 6
Required fraction = 5/6
- 3. If a fraction's numerator is increased by 1 and the denominator is increased by 1 and denominator is increased by 2 then the fraction becomes 2/3. But when the numerator is increased by 5 and the denominator is increased by 1, then the fraction becomes 5/4. What is the value of the original fraction?
Options- A. 3/7
- B. 5/8
- C. 5/7
- D. 6/7 Discuss
Correct Answer: 5/7
Explanation:
Let the numerator and denominator be p and q respectively.
Then, (p + 2) / (q + 3) = 7/9
? 9(p + 2) = 7(q +3)
? 9p - 7q = 3 ....(i)
Again, (p - 1) / (q - 1) = 4/5
? 5p - 4q = 1 ....(ii)
Solving (i) and (ii) we get,
p = 5, q = 6
Required fraction = 5/6
- 4. The value of (9 2 x 18 4) / 3 16 is?
Options- A. 2/3
- B. 4/9
- C. 16/81
- D. 32/243 Discuss
Correct Answer: 16/81
Explanation:
Given expression = [(32)2 x (3 x 3 x 2)4] / 316
= (34 x 38 x 24) / 316
= 24 / 34 = 16 / 81
- 5. A man spends (1/7)th of his salary on food, half of the remaining on clothing and (1/3)rd of the remaining on entertainment. He is still left with Rs. 600. How much does he spend on entertainment?
Options- A. Rs. 600
- B. Rs. 450
- C. Rs. 300
- D. Rs. 700 Discuss
Correct Answer: Rs. 300
Explanation:
Let man's salary be Rs. N
Money spend on food =N/7
Money spends on clothing = (N - N/7) x 1/2 = (6N/7) x (1/2) =3N/7
Money spend on entertainment = (N - N/7 - 3N/7)/3 = (7N - 4N)/7 = N/7
Now, money left =600
? N - N/7 - 3N/7 - N/7 = 600
? 7N - 5N/7 = 600
? N = 600 x 7/2 = Rs. 2100
? Money spend on entertainment = 1/7 x 2100 = Rs. 300
- 6. If a fraction is multiplied by itself and then divided by the reciprocal of the same fraction, the result is 18 26/ 27. find the fraction?
Options- A. 8/27
- B. 11/3
- C. 22/3
- D. 32/3 Discuss
Correct Answer: 22/3
Explanation:
If the required fraction be N.
Then, (N x N) / (1/N) = 1826/27
? N3 = 512 / 27
? N = 8/3 = 22/3
- 7. A lamppost is divided into three parts, the first part is (1/3)rd of the whole length, second (3/8)th of the first and the third is 6 m 50 cm. The length of the lamppost is?
Options- A. 15 m
- B. 10 m
- C. 12 m
- D. 131/2 Discuss
Correct Answer: 12 m
Explanation:
Let the length of lamppost = L m
Then,first part = L/3
and second part = (3/8) x L/3 = L/8
and third part = 6 m 50 cm = 6.50 m
First part + second part + Third part = length of lamppost
? L/3 + L/8 + 6.5 = L
? L - L/3 - L/8 =6.5
? (24L - 8L - 3L)/24 = 6.5
? 13L/24 = 6.5
? L = (65.x 24)/13 = 12 m
- 8. Find the value of 27 x 1. 2 x 5.526 2 x 0. 6 .
Options- A. 121.57
- B. 121.75
- C. 121.75
- D. None of these Discuss
Correct Answer: None of these
Explanation:
27 x 1.2 x 5.5262 x 0.6
= 27 x [(12 - 1) / 9] x [(55262 - 5526)/9000] x (6/9)
= (27 x 11)/9 x (49736/9000) x (6/9)
= 1094192 / 9000
= 121.576888...
= 121.5768
- 9. How many pieces of 13.2 cm can be cut from a 330 cm long rod?
Options- A. 25
- B. 28
- C. 21
- D. 35 Discuss
Correct Answer: 25
Explanation:
Total length of the rod = 330 cm
Length of a piece = 13.2 cm.
Required number of pieces = Total length/Length of a piece ;
Required number of pieces = 330/13.2 = 25
- 10. 1/8th part of a pencil is black, half of the remaining is white. If the remaining part is blue and length of this blue part is 3 1/ 2cm, then find the length of the pencil?
Options- A. 6 cm
- B. 7 cm
- C. 8 cm
- D. 9 cm Discuss
Correct Answer: 8 cm
Explanation:
Let the total length of pencil = L cm
Then, black part = L/8
? Remaining part = L - L/8 = 7L/ 8
and White part = (7L/8)/2 = 7L/8
? Remaining part = L - (L/8 + 7L/16) = 7L/16
? length of blue part = 7L/16
According to the question,
7L/16 = 31/2
? 7L/16 = 7/2
? L =8
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