RBI GRADE ‘B’ OFFICER’S EXAM Held on : 2008 (Part-III)

Total Questions: 50

1. What should come in place of question mark (?) in the following number series?

13 14 30 93 376 1885 ?

Correct Answer: (3) 11316
Solution:The given number series
is based on the following pattern:
13 x 1 + 1 = 14
14 x 2 + 2 = 30
30 x 3 + 3 = 93
93 x 4 + 4 = 376
376 x 5 + 5 = 1885
∴ ? = 1885 x 6 + 6 = 11316
Hence, number 11316 will replace the question mark.

2. 4 6 9 13.5 20.25 30.375 ?

Correct Answer: (2) 45.5625
Solution:

3. 400    240    144   86.4 51.84    31.104 ?

Correct Answer: (4) 18.6625
Solution:

4. 9  4.5  4.5  6.75  13.5  33.75 ?

Correct Answer: (1) 101.25
Solution:

5. 705  728  774  843  935  1050 ?

Correct Answer: (5) None of these
Solution:705 + 1 x 23 = 728
728 + 2 x 23 = 774
774 + 3 x 23 = 843

843 + 4 x 23 = 935
935 + 5 x 23 = 1050
∴ ? = 1050 + 6 x 23
= 1050 + 138 = 1188

6. Each of the questions below consists of a question and two statements numbered I and II given below it. You have to decide whether the data provided in the statements are sufficient to answer the question. Read the question and both the statements and ___.

Give answer (1) if the data in statement I alone are sufficient to answer the question, while the data in statement II alone are not sufficient to answer the question.

Give answer (2) if the data in statement II alone are sufficient to answer the question, while the data in statement I alone are not sufficient to answer the question.

Give answer (3) if the data either in statement I alone or in statement II alone are sufficient to answer the question.

Give answer (4) if the data even in both the statements I and II together are not sufficient to answer the question.

Give answer (5) if the data in both the statements I and II together are necessary to answer the question.

Train 'A' running at a certain speed crosses another train 'B' running at a certain speed in the opposite direction in 12 seconds. What is the length of train 'B' ?

I. The length of both the trains together is 450 metres.
II. Train 'A' is slower than train 'B'.

Correct Answer: (4)
Solution:Time taken in crossing each other
= Total length of trains/Relative speed

The information given in both statements is not sufficient as length of train A and individual speed of each train are required.

7. Area of a rectangle is equal to the area of a right angled triangle. What is the length of the rectangle ?

I. The base of the triangle is 40 cms.
II. The height of the triangle is 50 cms.

Correct Answer: (4)
Solution:Area of rectangle = Area of triangle.
From the information given in both the statements, we can find area of triangle or
area of rectangle. For finding length, breadth is required, which is not known.

8. What was the total compound interest on a sum after three years ?

I. The interest after one year was Rs. 100/- and the sum was Rs. 1,000/-.
II. The difference between simple and compound interest on a sum of Rs. 1,000/- at the end of two years was Rs. 10/-.

Correct Answer: (3)
Solution:From the statement I,

r = 100 × 100/1000 = 10%
Thus we have,
P = Rs. 1000, r = 10%,
t = 3years
Hence, C.I. can be deter-
mined
From the statement II.

S.I. = 1000 x r x 2/100 = 20r

⇒ 2000r + r² - 200r = 100
⇒ r = 10
Hence, C.I. can be determined

9. What is the two digit number where the digit at the unit place is smaller ?

I. The difference between the two digits is 5.
II. The sum of the two digits is 7.

Correct Answer: (5)
Solution:Let the unit's digit be x and
ten's digit be y and x < y.
... Number = 10y + x
From statement I,
y - x = 5 ...(i)
From statement II,
y + x = 7 ...(ii)

From (i) and (ii), x, y can be calculated and two digit number can be found.

10. What is the speed of the boat in still water ?

I. It takes 2 hours to cover distance between A and B downstreams.
II. It takes 4 hours to cover distance between A and B upstreams.

Correct Answer: (4)
Solution:Let the distance between
A and B be z km.
Again, let speed of boat in still water be x kmph and that of stream be y kmph.
∴ Rate downstream
= (x + y) kmph
Rate upstream = (x - y) kmph
From statement I,

z/(x + y) = 2  (i)

From statement II

z/(x - y) = 4  (ii)