Logical Reasoning set 4

The logical reasoning, also known as critical thinking or analytic reasoning, involves one's ability to isolate and identify the various components of any given argument.So, it is not a surprise that the logical reasoning questions commonly appear in any placement tests, competitive exams or entrance exams.

1) Jack,Doug and Ann, 3 children had a running race while returning from school.Mom asked who won the race. Then Jack replied" I wont tell u.I wil give u a clue,When Ann takes 28 steps Doug takes 24 steps, meantime I take 21 steps. Jack explained that his 6 steps equals Droug's 7 steps and Ann's 8 steps. Who won the race?

i) Jack

wrong answer

ii) Ann

wrong answer

iii) Jack and Ann 

wrong answer

iv) Doug

right answer

solution: iv) Doug

explanation :

Here distance of the race means Ann has to take 28 steps, Doug 24, and Jack 21.
In the time it takes Jack to do 6 steps, Doug does 7, and Ann does 8.

Thus;

Jack takes 21/6 = 3.5 units of time to complete the distance
Doug takes 24/7 = 3.428571 rec. units of time
Ann takes 28/8 = 3.5 units of time

So Doug wins.

look at steps

Ann steps = 8,16,24,28 --- finished by 3 & half full steps

Doug steps=7,14,21,24 --- finished before 3 & half full steps

Jack steps= 6,12,18,21 --- finished by 3 & half full steps

Hence Doug won the race.

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2) A man fixed an appointment to meet the manager, Manager asked him to come two days after the day before the day after tomorrow. Today is Friday. When will the manager expect him?

A) Tuesday

wrong answer

B) Saturday

wrong answer

C) Wednesday

wrong answer

D) Monday

right answer

solution: D) Monday

explanation:

  1        2         3          4        5         6       7
sun     mon     tue      wed     thu      fri   sat

today is Friday = 6
By question
day after tomorrow is sunday
day before sunday is saturday
now 2 days after saturday is monday.
hence answer is monday.

[Don't confuse it with Tuesday.the correct answer is Monday]

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3) 2 men r playing tossing a coin. if one of them wins he gets 1$ frm the loser. at the end of a no. of games one of them had 3$ and the other won 3 times. how many games did they play?

A) 6

wrong answer

B) 24

wrong answer

C) 9

right answer

D) 7

wrong answer

solution: 9

explanation:

Let and A and B are playing and A has 3$ and B won 3 times.

Total money earn by A = no of games A won - no of games A loss
if A loss game means B won.
Therefore
Total money earn by A = no of games A won - no of games B won
3 = no of games A won -3
no of games A won=6
So
A won = 6 games
B won = 3 games

Hence total no of games is 9.

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4)A lady goes for shopping. She bought some shoestrings. 4 times the number of shoestrings, she bought pins and 8 times, handkerchiefs. She paid each item with their count as each piece's cost. She totally spent Rs. 3.24. How many handkerchiefs did she buy? 

A) 16

right answer

B) 20 

wrong answer

C) 18 

wrong answer

D) 8

wrong answer

solution: 16

explanation:

say she has bought x amount of shoestrings
pin=4x
handkerchiefs=8x
She paid each item with their count as each piece's cost
so cost of shoestring=x*x
pin=4x*4x
handkerchiefs=8x*8x
so x*x+4x*4x+8x*8x=3.24 =324paisa
x*x=324/81
x=2
handkerchiefs she bought=8*x=16

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5) A woman says " my age is my husbands age reversed. if u take the difference between my age and my husband's it will be equal to one by eleventh of the sum of our ages. what is my age? "

A) 45

right answer

B) 35 

wrong answer

C)54

wrong answer

D) 63

wrong answer

solution: 200

explanation:

Let husband's age be: 10x+y
Wife's age : 10y+x
therefore according to question: (10x+y)-(10y+x)= 1/11(10x+y + 10y+x)
or,(x+y)/(x-y)=9/1
By componendo-dividendo : x/y=5/4, as x a nd y are single digit, so, x=5 and y=4
So husband's age is 54 and wife's age is 45.

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6) A camel must travel 15 miles in order to reach the nearest city. She have 45 bananas with her but can carry only 15 at a time. Also she eat 1 banana /mile. Then the maximum no of bananas that can be transported to the city?

A) 4

wrong answer

B) 6

wrong answer

C) 8

right answer

D) 12

wrong answer

solution:  8

explanation:

Have the camel travel 3 miles with 15 bananas. She will eat 3.
Drop off 9 bananas at the 3 mile marker, give the camel 3 bananas for the trip back and head to the start. Pick up 15 more bananas.
The camel eats 3 as you head to the 3 mile marker. Drop off another 9, give the camel 3 for the trip back, and head back to get the other 15.
Load the last 15 bananas up, and head for mile 3. The camel eats 3. You now have 9+9+12 = 30 bananas and are 12 miles from the city.

Load up 15 bananas and travel another 5 miles, to mile 8. The camel eats 5 bananas. Drop off 5 bananas, leaving 5 bananas to feed the camel for the trip back. Go back up to mile 3 and load up the last 15 bananas, and travel again to mile 8. The camel eats 5 bananas. You now have 15 bananas and are at mile 8.

Finally, take all 15 bananas and head the rest of the way. You are at mile 8 so you have 7 miles to go. The camel eats 7 bananas, leaving you with 8 bananas when you arrive.

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7) The length of a rectangle is increased by 60%. By what % would the width have to be decreased to maintain the same area?

A) 60%

wrong answer

B) 30%

wrong answer

C) 37.5%

wrong answer

D) 30%

right answer

solution:  37.5%

explanation:

length of a rectangle is increased by 60%. the width is to be decreased to x% to maintain the same area

Area of rectangle = length * width
length of a rectangle is increased by 60% means (60/100)length
therefore new length is 1.6*length
and new width is (x/100)*width
now area of both rectangle is same.
length * width = (1.6*length)* ((x/100)*width)
x= 100/1.6 = 62.5

Hence breadth should be decreased by (100-62.5) = 37.5 %

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8) A and B are shooters and having their exam. A and B fall short of 10 and 2 shots respectively to the qualifying mark. If each of them fired atleast one shot and even by adding their total score together, they fall short of the qualifying mark, what is the qualifying mark?

A) 9

wrong answer

B) 10

wrong answer

C) 11

right answer

D) 1

wrong answer

solution:  11

explanation:

If a & b are scores of A and B respectively and Q is qualifying score, then
Q = a+10, a = Q-10
Q=b+2, b= Q-2
Q = a+b+1 = Q-10+Q-2+1= 2Q-11
Q=11
a=1
b=9

Hence 11 is the qualifying mark.

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9) What is the sum of first 100 terms which are common to both the progressions? 17,21,25,... and 16,21,26,...

A) 120000

wrong answer

B) 100000

wrong answer

C) 101111

wrong answer

D) 101100

right answer

solution:  101100.

explanation:

1st series is  17,21,25,...
2nd series is 16,21,26,...
Common  difference  of  1st series = 4.
common  difference  of  2nd series = 5.
Now,  common  difference  of  sequence of  identical  terms = LC.M.  of  4  and  5 = 20.
First  term = 21,
Sum of 1st 100 term = (100/2)[ 2 x 21 + (100-1) x 20 ]= 101100.

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10) A car owner buys petrol at Euro 7.50, Euro 8 and Euro 8.50 per litre for three successive years. What approximately is the average cost per litre of petrol if he spends Euro 4000 each year?

A) Euro 8.50

wrong answer

B) Euro 7.98

right answer

C) Euro 8

wrong answer

D) Euro 9

wrong answer

solution:  Euro 7.98

explanation:

petrol used in 1st year = 4000/7.5 = 533.33 litre
petrol used in 2nd year = 4000/8   = 500 litre
petrol used in 3rd year = 4000/8.5 = 470.59 litre

Total petrol used in 3 years = 533.33 + 500 + 470.59 = 1503.92 litre
Total money spend on petrol in 3 years = 3*4000 =12000 Euro

Average cost per litre = 12000/1503.92 =  7.98 Euro

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