LINEAR EQUATIONS IN ONE AND TWO VARIABLES (CDS)

Total Questions: 41

21. The cost of 2.5 kg rice is ` 125. The cost of 9 kg rice is equal to that of 4 kg pulses. The cost of 14 kg pulses is equal to that of 1.5 kg tea. The cost of 2 kg tea is equal to that of 5 kg nuts. What is the cost of 11 kg nuts? [2016 (II) Evening Shift ]

Correct Answer: (d) ₹4620
Solution:We have, cost of 2.5 kg rice = ₹125

22. In an examination, a student was asked to divide a certain number by 8. By mistake he multiplied it by 8 and got the answer 2016 more than the correct answer. What was the number? [2016 (II) Evening Shift ]

Correct Answer: (b) 256
Solution:Let x be the number, then 8x = x/8 + 2016

23. The value of k, for which the system of equations 3x - ky - 20 = 0 and 6x - 10y + 40 = 0 has no solution, is [2016 (I) Morning Shift]

Correct Answer: (c) 5
Solution:

24. There are three brothers. The sums of ages of two of them at a time are 4 year, 6 year and 8 year. The age difference between the eldest and the youngest is [2016 (I) Morning Shift]

Correct Answer: (b) 4 year
Solution:Let the ages of three brothers be a, b and c.

25. Let a two digits number be k times the sum of its digits. If the number formed by interchanging the digits is m times the sum of the digits, then the value of m is [2016 (I) Morning Shift]

Correct Answer: (c) 11 − k
Solution:Let the unit’s place digit be y and ten’s place digit be x.


26. The annual incomes of two persons are in the ratio 9 : 7 and their expenses are in the ratio 4 : 3. If each of them saves ₹2000 per year, then what is the difference in their annual incomes? [2016 (I) Morning Shift]

Correct Answer: (a) ₹4000
Solution:Let annual incomes of two persons be 9x and 7x and expenses be 4y and 3y, respectively.

27. Solve the following equation [2016 (I) Morning Shift]

Correct Answer: (c)
Solution:

28. Solve the following equation [2016 (I) Morning Shift]

Correct Answer: (d) 9
Solution:We have, x − y = 8

29. A tin of oil was 4/5 full. When 6 bottles of oil were taken out from this tin and 4 bottles of oil were poured into it, it was 3/4 full. Oil of how many bottles can the tin contain? (All bottles are of equal volume) [2015 (II) Evening Shift]

Correct Answer: (b) 40
Solution:Let a tin of oil contain x bottles of oil.

30. The number of pairs (x, y), where x, y are integers satisfying the equation 21x + 48y = 5, is [2015 (II) Evening Shift]

Correct Answer: (a) Zero
Solution: