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Q:

In a 500 m race, the ratio of the speeds of two contestants A and B is 3 : 4. A has a start of 140 m. Then, A wins by:

A) 60m	B) 40m
C) 20m	D) 10m

Answer & Explanation Answer: C) 20m

Explanation:

To reach the winning post A will have to cover a distance of (500 - 140)m, i.e., 360 m.

While A covers 3 m, B covers 4 m.

While A covers 360 m, B covers (4/3)*360 = 480 m.

Thus, when A reaches the winning post, B covers 480 m and therefore remains 20 m behind.

A wins by 20 m.

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Filed Under: Races and Games

Q:

A and B take part in 100 m race. A runs at 5 kmph. A gives B a start of 8 m and still beats him by 8 seconds. The speed of B is:

A) 5.15 kmph	B) 4.14 kmph
C) 4.25 kmph	D) 4.4 kmph

Answer & Explanation Answer: B) 4.14 kmph

Explanation:

A's speed = (5*5/15)m/sec = (25/18)m/sec

Time taken by A to cover 100 m = (100*18/15)sec = 72sec

Time taken by B to cover 92 m = (72 + 8) = 80 sec.

B's speed =(92/80*18/5)kmph =4.14kmph

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Filed Under: Races and Games

Q:

In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:

A) 21/46	B) 1/5
C) 3/25	D) 1/50

Answer & Explanation Answer: A) 21/46

Explanation:

Let , S - sample space E - event of selecting 1 girl and 2 boys.

Then, n(S) = Number ways of selecting 3 students out of 25

= $25 C_{3}$

= 2300.

n(E) = $10 C_{1} \times 15 C_{2}$ = 1050.

$\therefore$ P(E) = n(E)/n(s) = 1050/2300 = 21/46

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Filed Under: Probability

Q:

In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:

A) 21/46	B) 1/5
C) 3/25	D) 1/50

Answer & Explanation Answer: A) 21/46

Explanation:

Let S be the sample space and E be the event of selecting 1 girl and 2 boys.

Then, n(S) = Number ways of selecting 3 students out of 25

= $25 C_{3}$ = 2300.

n(E)= $10 C_{1} * 15 C_{2}$ = 1050.

P(E) = n(E)/n(s) = 1050/2300 = 21/46

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Filed Under: Probability

Q:

Three unbiased coins are tossed. What is the probability of getting at most two heads?

A) 3/4	B) 7/8
C) 1/2	D) 1/4

Answer & Explanation Answer: B) 7/8

Explanation:

Here S = {TTT, TTH, THT, HTT, THH, HTH, HHT, HHH}

Let E = event of getting at most two heads.

Then E = {TTT, TTH, THT, HTT, THH, HTH, HHT}.

P(E) =n(E)/n(S)=7/8.

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Filed Under: Probability

Q:

What would be the least number of years in which the simple interest on Rs.2600 at % will be an exact number of rupees ?

A) 2	B) 3
C) 4	D) 5

Answer & Explanation Answer: B) 3

Explanation:

$S . I = R s . [2600 * \frac{20}{3} * \frac{1}{100} * t]$

$S . I = R s . [\frac{520}{3} * t]$

t=3

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Filed Under: Compound Interest
Exam Prep: Bank Exams
Job Role: Bank PO

Q:

A sum was put at simple interest at a certain rate for 10 years . Had it been put at 5% higher rate , it would have fetched Rs.600 more. What was the Sum?

A) Rs.1200	B) Rs.1300
C) Rs.1400	D) Rs.1500

Answer & Explanation Answer: A) Rs.1200

Explanation:

At 5% more rate, the increase in S.I for 10 years = Rs.600 (given)

So, at 5% more rate, the increase in SI for 1 year = 600/10 = Rs.60/-

i.e. Rs.60 is 5% of the invested sum

So, 1% of the invested sum = 60/5

Therefore, the invested sum = 60 × 100/5 = Rs.1200

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Filed Under: Simple Interest
Exam Prep: Bank Exams
Job Role: Bank PO

Q:

A sum of Rs.1550 was lent partly at 8% p.a. simple interest. The total interest received after 3 years was Rs.300. The ratio of the money lent at 5% to that lent at 8% is :

A) 5:8	B) 6:7
C) 16:15	D) 17:18

Answer & Explanation Answer: C) 16:15

Explanation:

let the sum lent at 5% be Rs.x and that lent at 8% be Rs.(1550-x). then,

Interest on x at 5% for 3 years + interest on (1550-x) at 8% for 3 years = 300

$\frac{x * 5 * 3}{100} + \frac{(1500 - x) * 8 * 3}{100} = 300$

x=800

Required ratio = x : (1550-x) = 800 : (1550-800) = 800 : 750 = 16 : 15

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Filed Under: Simple Interest
Exam Prep: Bank Exams
Job Role: Bank PO

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