21. What is the value of k for which the following system of equations has no solution:
2x-8y = 3 and kx +4y = 10
Answer: -1
Explanation:Here is no explanation for this answer
Workspace
Green Valley Motor
22. How many 3 - digit even number can you form such that if one of the digits is 5, the following digit must be 7?
Answer: 365
Explanation:Here is no explanation for this answer
Workspace
Green Valley Motor
23. Alord got an order from a garment manufacturer for 480 Denim Shirts. He brought 12 sewing machines and appointed some expert tailors to do the job. However, many didn't report to duty. As a result, each of those who did, had to stitch 32 more shirts than originally planned by Alord, with equal distribution of work. How many tailors had been appointed earlier and how many had not reported for work?
Answer: 10, 4
Explanation:Here is no explanation for this answer
Workspace
Green Valley Motor
24. Fifty college teachers are surveyed as to their possession of colour TV, VCR and tape recorder. Of them, 22 own colour TV, 15 own VCR and 14 own tape recorders. Nine of these college teachers own exactly two items out of colour TV, VCR and tape recorder; and, one college teacher owns all three. How many of the 50 teachers own none of the three, colour TV, VCR or tape recorder?
Answer: 10
Explanation:Here is no explanation for this answer
Workspace
Green Valley Motor
25. Three times the first of three consecutive odd integers is 3 more than twice the third. What is the third integer?
Answer: 15
Explanation:Suppose consecutive odd integers are: (a-2), a, (a+2)
Hence, 3a-6 = 2(a+2) + 3 => a=13
a+2 = 15
Workspace
Green Valley Motor
26. A solid metallic cube is melted to form five solid cubes whose volumes are in the ratio 1 : 1 : 8 : 27 : 27. The percentage by which the sum of the surface areas of these five cubes exceeds the surface area of the original cube is nearest to
Answer: 50
Explanation:Here is no explanation for this answer
Workspace
Green Valley Motor
27. Let ABC be a right-angled isosceles triangle with hypotenuse BC. Let BQC be a semi-circle, away from A, with diameter BC. Let BPC be an arc of a circle centered at A and lying between BC and BQC. If AB has length 6 cm then the area, in sq cm, of the region enclosed by BPC and BQC is
Answer: 18
Explanation:Here is no explanation for this answer
Workspace
Green Valley Motor
28. A class consists of 20 boys and 30 girls. In the mid-semester examination, the average score of the girls was 5 higher than that of the boys. In the final exam, however, the average score of the girls dropped by 3 while the average score of the entire class increased by 2. The increase in the average score of the boys is
Answer: 9.5
Explanation:Here is no explanation for this answer
Workspace
Green Valley Motor
29. If a and b are integers of opposite signs such that (a+3)^2 : b^2 = 9 : 1 and (a - 1)^2 : (b-1)^2 = 4:1 . then the ratio of a^3 : b^2
Answer: 25:4
Explanation:Here is no explanation for this answer
Workspace
Green Valley Motor
30. Suppose, C1, C2, C3, C4, and C5 are five companies. The profits made by Cl, C2, and C3 are in the ratio 9 : 10 : 8 while the profits made by C2, C4, and C5 are in the ratio 18 : 19 : 20. If C5 has made a profit of Rs 19 crore more than C1, then the total profit (in Rs) made by all five companies is
Answer: 438 crore
Explanation:C1 : C2 : C3 = 9 : 10 : 8 ... i
C2 : C4 : C5 = 18 : 19 : 20 ... ii
Let's multiply i by 9 and ii by 5
C1 : C2 : C3 = 81 : 90 : 72
C2 : C4 : C5 = 90 : 95 : 100
Therefore, C1 : C2 : C3 : C4 : C5 = 81 : 90 : 72 : 95 : 100
Given,
100x - 81x = 19
x = 1
Hence, total profit = 100 + 95 + 72 + 90 + 81 = 438
Workspace
Green Valley Motor
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