The sum of the dimensions of a room (i.e. length, breadth and height) is 18 metres and its length, breadth and height are in the ratio of 3 : 2 : 1 respectively. If the room is to be painted at the rate of Rs. 15 per m2, what would be the total cost incurred on painting only the four walls of the room (in Rs.)?
3250
2445
1350
2210
2940
Answer : Option C.
Ratio of length : breadth : height = 3 : 2 : 1
Breath = 2/6×18 = 6
Height = 1/6×18 = 3
Area of four walls = 2h×(l+b) = 2×3(9+6) = 90
Total cost of painting four walls = 90×15 = 1350
B is 4/3 times as efficient as A. If A can complete 5/8th of a given task in 15 days, what fraction of the same task would remain incomplete if B works on it independently for 10 days only?
3/4
2/3
5/8
4/9
2/3
Answer : Option D.
B is 4/3 times as efficient of A.
Ratio of time taken by A and B, A: B is 4:3.
A can complete 5/8th of a given task in 15 days
A can do alone his work in = 8/5× 15= 24 days
Therefore, B can do this work= 18
B works independently for 10 days only, thus work done = 10/18 = 5/9
Remaining work (incomplete) = 1-5/9 = 4/9
In a class, the average weight of boys is 64 kg and that of 75 girls is 70 kg. After a few days, 60% of the girls and 30% of the boys leave. What would be the new average weight of the class (in kg)? Assume that the average weight of the boys and the girls remain constant throughout.
63
66.5
68.5
65.5
Can't be determined
Answer : Option E.
In this question, number of boys is not mentioned .So, we can’t find new average.
382 380 374 356 302 ?
212
240
140
201
158
Answer : Option C.
The pattern is as follows:
382 – 2 = 380
380 – 6 = 374
374 – 18 = 356
356 – 54 = 302
302 – 162 = 140
3 9 45 315 ? 31185
2465
2685
2955
2835
2785
Answer : Option D.
The pattern is as follows:
3 * 3 = 9
9 * 5 = 45
45 * 7 = 315
315 * 9 = 2835
Answer : Option B.
The pattern is as follows:
12 + 2 = 14
14 + 4 = 18
18 + 8 = 26
26 + 16 = 42
42 + 32 = 74
In how many ways can 3 integers be selected from the set {1, 2, 3, …….., 37} such that sum of the three integers is an odd number?
3876
7638
6378
1938
969
Answer : Option A.
There are 18 even and 19 odd numbers in the given set. For sum to be odd either all 3 numbers should be odd or 2 of them even and one odd. This is possible in 19C3 + (18C2 × 19C1) = 3876 ways
There are 13 married couples, 5 single men and 7 single women in a party. Every man shakes hand with every woman once, but no one shakes hand with his wife. How many handshakes took place in the party?
247
347
360
191
100
Answer : Option B.
Any single man will have = 13 + 7 = 20 options.
Total number of handshakes by single men = 20 × 5= 100. Any married man will have 12 + 7 = 19 options.
Total number of handshakes by married men = 19 × 13 = 247. Total number = 247 + 100 = 347.
A and B are two towns. A car goes from A to B at a speed of 64 km/hr and return to A at a slower speed. If its average speed for the whole journey is 56 km/hr, it returned with speed
152.54 km/hr
47.52 km/hr
49.78 km/hr
53 km/hr
57 km/hr
Answer : Option A.
Let the speed on the return journey be x km/hr. Then, 56 = = 7(64 + x) = 16x or 9x = 448 ∴ x = 448/9 = 49.78 km/hr.
A train travels 225 km in 3.5 hours and 370 km in 5 hours. Find the average speed of train.
80 km/hr
60 km/hr
70 km/hr
63 km/hr
50 km/hr
Answer : Option C.
Here, x1 = 225, x2 = 370, T1 = 3.5 and T2 = 5. ∴ Average speed of train = (X1 + X2)/(T1 + T2) = (225+370)/(3.5+5) = 70 km/hr.
= 
7(64 + x) = 16x or 9x = 448 ∴ x = 448/9 = 49.78 km/hr.
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