[B].
[C].
[D].
Answer: Option A
Explanation:
Subtract 20, 25, 30, 35, 40, 45 from successive numbers.
So, 0 is wrong.
[B].
[C].
[D].
Answer: Option C
Explanation:
Let total number of children be x.
| Then, x x | 1 | x = | x | x 16 x = 64. |
| 8 | 2 |
| Number of notebooks = | 1 | x2 = | 1 | x 64 x 64 | = 512. | ||
| 8 | 8 |
[B].
[C].
[D].
Answer: Option A
Explanation:
| Here a = 3 and r = | 6 | = 2. Let the number of terms be n. |
| 3 |
Then, tn = 384 arn-1 = 384
3 x 2n – 1 = 384
2n-1 = 128 = 27
n – 1 = 7
n = 8
Number of terms = 8.
[B].
[C].
[D].
Answer: Option C
Explanation:
3x – y = 27 = 33 x – y = 3 ….(i)
3x + y = 243 = 35 x + y = 5 ….(ii)
On solving (i) and (ii), we get x = 4.
[B].
[C].
[D].
Answer: Option B
Explanation:
| This is a G.P. in which a = 2, r = | 22 | = 2 and n = 9. |
| 2 |
| Sn = | a(rn – 1) | = | 2 x (29 – 1) | = 2 x (512 – 1) = 2 x 511 = 1022. |
| (r – 1) | (2 – 1) |
| 1 | day |
| 24 |
[B].
| 7 | day |
| 24 |
[C].
| 3 | 3 | days |
| 7 |
[D].
Answer: Option C
Explanation:
| Formula: If A can do a piece of work in n days, then A’s 1 day’s work = | 1 | . |
| n |
| (A + B + C)’s 1 day’s work = | 1 | + | 1 | + | 1 | = | 7 | . | ||
| 24 | 6 | 12 | 24 |
| Formula: If A’s 1 day’s work = | 1 | , | then A can finish the work in n days. |
| n |
| So, all the three together will complete the job in | 24 | days | = | 3 | 3 | days. | 7 | 7 |
[B].
[C].
[D].
Answer: Option C
Explanation:
| Given Exp. | = [(a + b)2 – 4ab], where a = 476 and b = 424 |
| = [(476 + 424)2 – 4 x 476 x 424] | |
| = [(900)2 – 807296] | |
| = 810000 – 807296 | |
| = 2704. |