[B].
[C].
[D].
Answer: Option A
Explanation:
Alternatively 23 is added and 17 is subtracted from the terms. So, 634 is wrong.
[B].
[C].
[D].
Answer: Option B
Explanation:
| log10 80 | = log10 (8 x 10) |
| = log10 8 + log10 10 | |
| = log10 (23 ) + 1 | |
| = 3 log10 2 + 1 | |
| = (3 x 0.3010) + 1 | |
| = 1.9030. |
[B].
[C].
[D].
Answer: Option C
Explanation:
Let the speed of each train be x m/sec.
Then, relative speed of the two trains = 2x m/sec.
| So, 2x = | (120 + 120) |
| 12 |
2x = 20
x = 10.
| Speed of each train = 10 m/sec = | 10 x | 18 | km/hr = 36 km/hr. | ||
| 5 |
[B].
[C].
[D].
Answer: Option B
Explanation:
Let the length of the train be x metres and its speed by y m/sec.
| Then, | x | = 15 y = | x | . |
| y | 15 |
| x + 100 | = | x | |
| 25 | 15 |
15(x + 100) = 25x
15x + 1500 = 25x
1500 = 10x
x = 150 m.
[B].
[C].
[D].
Answer: Option C
Explanation:
| Speed = | 78 x | 5 | m/sec | = | 65 | m/sec. | ||||
| 18 | 3 |
Time = 1 minute = 60 seconds.
Let the length of the tunnel be x metres.
| Then, | 800 + x | = | 65 | ||
| 60 | 3 |
3(800 + x) = 3900
x = 500.
[B].
[C].
[D].
Answer: Option A
Explanation:
Let Arun’s weight by X kg.
According to Arun, 65 < X < 72
According to Arun’s brother, 60 < X < 70.
According to Arun’s mother, X <= 68
The values satisfying all the above conditions are 66, 67 and 68.
| Required average = | 66 + 67 + 68 | = | 201 | = 67 kg. | ||||
| 3 | 3 |