How many terms are there in the G.P. 3, 6, 12, 24, ... , 384 ?
9
10
11
Answer: Option A
Explanation:
Then, tn = 384 arn-1 = 384
3 x 2n - 1 = 384
2n-1 = 128 = 27
n - 1 = 7
n = 8
Number of terms = 8.
9548 + 7314 = 8362 + (?)
Answer: Option C
9548 16862 = 8362 + x + 7314 x = 16862 - 8362 ----- = 8500 16862 -----
In a division sum, the remainder is 0. As student mistook the divisor by 12 instead of 21 and obtained 35 as quotient. What is the correct quotient ?
12
13
20
Answer: Option D
Number = (12 x 35)
Correct Quotient = 420 � 21 = 20
2 + 22 + 23 + ... + 29 = ?
Answer: Option B
The sum of even numbers between 1 and 31 is:
28
240
512
Let Sn = (2 + 4 + 6 + ... + 30). This is an A.P. in which a = 2, d = 2 and l = 30
Let the number of terms be n. Then,
a + (n - 1)d = 30
2 + (n - 1) x 2 = 30
n = 15.