[B].
[C].
[D].
Answer: Option C
Explanation:
log 27 = 1.431
log (33 ) = 1.431
3 log 3 = 1.431
log 3 = 0.477
log 9 = log(32 ) = 2 log 3 = (2 x 0.477) = 0.954.
[B].
[C].
[D].
Answer: Option B
Explanation:
Let the required number of days be x.
Less persons, More days (Indirect Proportion)
More working hours per day, Less days (Indirect Proportion)
| Persons | 30 | : | 39 | :: 12 : x | |
| Working hours/day | 6 | : | 5 |
30 x 6 x x = 39 x 5 x 12
| x = | (39 x 5 x 12) |
| (30 x 6) |
x = 13.
[B].
[C].
[D].
Answer: Option D
Explanation:
35423 317 x 89 = 317 x (90 -1 )
+ 7164 = (317 x 90 – 317)
+ 41720 = (28530 – 317)
—– = 28213
84307
– 28213
—–
56094
—–
[B].
[C].
[D].
Answer: Option A
Explanation:
5a = 3125 5a = 55
a = 5.
5(a – 3) = 5(5 – 3) = 52 = 25.
[B].
[C].
[D].
Answer: Option C
Explanation:
Let the given number be 476 xy 0.
Then (4 + 7 + 6 + x + y + 0) = (17 + x + y) must be divisible by 3.
And, (0 + x + 7) – (y + 6 + 4) = (x – y -3) must be either 0 or 11.
x – y – 3 = 0 y = x – 3
(17 + x + y) = (17 + x + x – 3) = (2x + 14)
x= 2 or x = 8.
x = 8 and y = 5.
[B].
[C].
[D].
Answer: Option B
Explanation:
(112 + 122 + 132 + … + 202) = (12 + 22 + 32 + … + 202) – (12 + 22 + 32 + … + 102)
| Ref: (12 + 22 + 32 + … + n2) = | 1 | n(n + 1)(2n + 1) | |||
| 6 |
| = | 20 x 21 x 41 | – | 10 x 11 x 21 | ||
| 6 | 6 |
= (2870 – 385)
= 2485.