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Data Sufficiency Questions On Clocks

Data Sufficiency Questions On Clocks**A**. Statement 1 ALONE is sufficient, but statement 2 alone

**B**. Statement 2 ALONE is sufficient, but statement 1 alone

**C.**BOTH statements (1) and (2) TOGETHER

**D.**EACH statement ALONE

**E.**Statements (1) and (2) TOGETHER

1. What is the present time in the
clock?

1. The angle between the hour hand and the minute hand is 10

^{0}
2. The mirror reflection of the clock shows
the time 7:40

**Answer** : B

**Explanation :**

Using Statement 1 alone,

The two hands in a clock form an angle of 10 degrees twice in an hour.

So, statement 1 alone is not sufficient.

Using Statement 2 alone,

The time in the mirror reflection of the clock is 7:40.

We can find the actual time by
subtracting the time in the mirror reflection from 12:00

So statement 2 alone is sufficient to
get the question.

Therefore, the answer is A

2. Find the time shown in a wall clock?

1. The angle between the two hands is 180

^{0}
2. The hour hand of the clock is between 7 and 8 on the dial

**Answer : C**

**Explanation :**

Using
Statement 1 alone,

The
two hands of the clock are at an angle of
180

^{0}. It happens only once every hour. But we cannot tell the time because the hour is not given.
So,
Statement 1 alone is not sufficient

Using
Statement 2 alone,

The
position of the hour hand is given, but the minute hand’s position is not
given.

So
statement 2 alone is not sufficient in getting the answer.

Combining
both statements,

The
hour hand is between 7 and 8, and the angle between the two hands is 180

^{0}.
The
angle 180

^{0}happens only once in one hour. Then we can find the present time in the clock.
Both
statements together are necessary to answer the question.

Therefore,
the answer is C

3. What is the angle between the hour
hand and the minute hand of the clock?

1. The two hands are
$\frac{50}{3}$ minute spaces apart.

2. The minute hand is
on 8, and the hour hand is between 4 and 5.

Answer : D

Explanation:

From statement 1 alone,

The two hands are $\frac{50}{3}$ minute spaces
apart.

1 minute space = 6

^{0}.
So the two hands are ($\frac{50}{3}$ x 6

^{0})= 100^{0}apart.
We can find the angle between the two
hands using the data given in statement 1 alone.

From statement 2 alone,

We can say that the time is 4:40

As the exact time is given, we can find
the angle between the two hands.

So statement 2 alone is sufficient to
answer the question.

Therefore, the answer is D

4. How many minutes does a clock lose or
gain in a day if it is set to correct time at noon today?

1. The clock shows
4:20 p.m when the time is 4 p.m today.

2. The clock gains 5
minutes every hour.

**Answer : D**

**Explanation :**

The
clock is showing the correct time at noon (12 p.m).

From
statement 1 alone,

The
clock shows 4:20 p.m when the time is 4 p.m.

So
the clock gains 20 minutes from 12 p.m.
to 4 p.m.

So
the clock gains 20 minutes in 4 hours => The clock gains 5 minutes in one
hour.

From
this, we can find the number of minutes the clock gains or loses in a day.

Statement
1 alone is sufficient to answer the question.

From
statement 2 alone,

The
clock gains 5 minutes every hour.

From
this information, we can find the number of minutes the clock gains in a day.

Statement
2 alone is sufficient to answer the question.

Therefore
the answer is D

5. How many minutes does clock gain in a
day? MAT September 1999

1.
The clock reads 6:00 when correct the time is 5: 48

2. The clock gains 40
seconds each hour

**Answer :**

**Explanation :**

The
clock reads 6:00 when the real-time is 5:48.

So
the clock gains time. But we don’t have
the information about the rate of time gained by the clock

Therefore,
we cannot find the time gained by the clock in 24 hours because we don’t know
the time at which the clock was set to the correct time.

So
statement 1 alone is not sufficient to get the answer

From
statement 2 alone,

The
clock gains 40 seconds every hour.

It
gains (24 x 40) = 960 seconds or 16 minutes in 24 hours or day

So
statement 2 alone is sufficient to get the answer

Therefore
, the answer is B

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__ Data Sufficiency Questions On Calendars__

__Data Sufficiency Questions On Calendars__
6. On which day of the week, Anil will
celebrate his birthday if his friend Komali celebrates her birthday on Monday
in the same year?

1.
Komali’s birthday comes 56 days after
Anil’s birthday in the year

2.
Komali’s birthday is on September 23

^{rd}and Anil’s birthday is on January 15^{th}
Answer
: A

Statement
1 alone :

Komali’s
birthday is on Monday.

From
statement 1 alone,

Anil’s
birthday is 56 days before Komali’s birthday

Anil’s
birthday will be on => Monday -56 = Monday

Therefore,
statement 1 alone is sufficient to get the answer.

From
statement 2 alone,

Komali’s
birthday is on September 23

^{rd}and is a Monday
Anil’s
birthday is on January 15

^{th}.
We
cannot find the day of the week on 15

^{th}January because it is not clear that the February month, which occurs in this period, has 28 days or 29 days.
So
data given in statement 2 is not sufficient to answer the question.

Therefore,
the answer is A

7. How many Sundays occur in a month in a leap year?

1.1

^{st}of the month is a Sunday
2.5

^{th}of the month is a Sunday**Answer : D**

**Explanation :**

The
year is a leap year. So February will have 29 days

From
statement 1 alone,

1

^{st}of the month is a Sunday.
So
Sundays in the month are on => 1

^{st}, 8^{th}, 15^{th}, 22^{nd}and 29^{th}
All
months in a leap year have 29

^{th}day. So there 5 Sundays in the month
So
statement 1 alone is sufficient to get the answer.

From
statement 2 alone,

5

^{th}of the month is a Sunday.
So
Sundays in the month are => 5

^{th}, 12^{th}, 19^{th,}and 26^{th}
It
is possible in any month of a year.

There
are 4 Sundays in the month

So
statement 2 alone is sufficient to get the answer

Therefore
, the answer is B

8. Is it a Tuesday today?

1.18

^{th}February of this year was a Wednesday
2. Today is Independence day
of India

**Answer : E**

**Explanation :**

Taking statement 1 alone :

18

^{th}February of the year was a Wednesday, but today’s date is not given.
So statement 1 alone is not sufficient
to get the answer

Taking statement 2 alone:

Today is 15

^{th}August.
We have no reference date or present
year, so we cannot find the day of the week today.

Combining both statements,

18

^{th}February of the year was a Wednesday, and today is 15^{th}August.
Yet we have no information whether the
February month in the period has 28 days or 29 days.

So even when both statements are
combined, we cannot find the answer.

Therefore, the answer is E

9. In August, public holidays are only
two. One is Independence Day, and the
other is Rakhi Pournami. How many total holidays will be there in the month?

1.
Only Sundays are holidays except for public holidays

2.18

^{th}March of the year is a Monday**Answer : C**

**Explanation :**

There are 2 public holidays in the
month.

From statement 1 alone,

All Sundays and only public holidays are
holidays. We don’t know the number of Sundays in August, so we can’t find the
number of holidays in the month.

From statement 2 alone,

18

^{th}March of the year is a Monday.
Hence, it can be found which day of the
week is 1

^{st}August.
But that will not answer the question.

So statement 2 alone is not sufficient

Combining both statements,

Only Sundays and public holidays are holidays.
We can find the number of Sundays in August , because from statement 2; we can
find which day of the week 1

^{st}August was.
Both statements together are sufficient
to get the answer.

Therefore, the answer is C

10. Is the year N a leap year?

1.
The year N is a multiple of 100

2.
The year N is a multiple of 400

**Answer : B**

**Explanation :**

From statement 1 alone:

N is a multiple of 100. Then N is a
century year.

1600 is a multiple of 100, and it is a
leap year.

1700 is a multiple of 100 but not a leap
year.

So we cannot determine whether N is a
leap year or not.

So data given in statement 1 alone is
not sufficient to get the answer.

From statement 2 alone:

If a year is exactly divisible by 400,
then it is a leap year.

400, 800, 1200, 1600, 2000 and 2400, etc.
are leap years.

So statement 2 alone is sufficient to
determine that N is a leap year.

Therefore, the answer is B