Solved CAT Questions (Arithmetic) - Set 9
It takes the pendulum of a clock 7 seconds to strike 4 o’clock. How much time will it take to strike 11 o’clock?
(a) 18 seconds
(b) 20 seconds
(c) 19.25 seconds
(d) 23.33 seconds
Let say it takes t seconds to strike once.
At 4 o'clock the pendulum should strike 4 times and it will take 3t seconds (Considering first strike happened at zero'th second)
3t = 7
t = 7/3
Similarly at 11 o'clock pendulum should strike 11 times and it will take 10t seconds (first strike happens at zero'th second and t is the time elapsed between each consecutive strike)
10 x 7/3 = 23.33 seconds
A man buys spirit at Rs. 60 per litre, adds water to it and then sells it at Rs. 75 per litre. What is the ratio of spirit to water if his profit in the deal is 37.5%?
(a) 9 : 1
(b) 10 : 1
(c) 11 : 1
(d) None of these
I L spirit cost 60 Rs
If he adds x L of water to it then the total quantity is (1 + x) L
At the rate of 75, this should yield 75 (1 + x) which is 37.5% higher than the cost price, 60 = 82.5
x = 82.5/75 = 0.1
So required ratio is 10 : 1
A and B walk from X to Y, a distance of 27 km at 5 kmph and 7 kmph respectively. B reaches Y and immediately turns back meeting A at Z. What is the distance from X to Z?
(a) 25 km
(b) 22.5 km
(c) 24 km
(d) 20 km
X ---------------- < d > ---------------------- Z --------------- < 27 - d > --------------- Y
here time taken is same.
d/5 = (27 + 27 - d)/7
d/5 = (54 - d)/7
7d = 270 - 5d
12d = 270
d = 270/12 = 22.5 km.
There is a leak in the bottom of the tank. This leak can empty a full tank in 8 hours. When the tank is full, a tap is opened into the tank which admits 6 litres per hour and the tank is now emptied in 12 hours. What is the capacity of the tank?
(a) 28.8 litres
(b) 36 litres
(c) 144 litres
(d) Cannot be determined
To empty a full tank - 8 hours
Time took for emptying the tank in the given question - 12 hours
Tap was open for 12 hours adding an extra 12 x 6 = 72 L of water into the tank.
Hence the extra 4 hours was required to empty this 72 L of water.
In 8 hours it can empty 72 x 2 = 144 L of water which is the capacity of the tank.
A dealer offers a cash discount of 20% and still makes a profit of 20%, when he further allows 16 articles to a dozen to a particularly sticky bargainer. How much percent above the cost price were his wares listed?
(d) 66 2/3%
say CP = 100
For 12 articles, CP = 12 x 100 = 1200
After 20% discount, SP = 1200 - 240 = 960
SP of 16 articles = 960
SP of 1 article = 60
20% profit means Actual CP = 60/1.2 = 50
Assumed CP = 100, Actual CP = 50
So it was listed 100% above the actual cost price
The winning relay team in a high school sports competition clocked 48 minutes for a distance of 13.2 km. Its runners A, B, C and D maintained speeds of 15 kmph, 16 kmph, 17 kmph, and 18 kmph respectively. What is the ratio of the time taken by B to than taken by D?
(a) 5 : 16
(b) 5 : 17
(c) 9 : 8
(d) 8 : 9
All runners covered the same distance.
Time taken is inversely proportional to speed
For B and D, ratio of time taken is 1/16 : 1/18 = 18 : 16 = 9 : 8
The rate of increase of the price of sugar is observed to be two percent more than the inflation rate expressed in percentage. The price of sugar, on January 1, 1994, is Rs. 20 per kg. The inflation rate for the years 1994 and 1995 are expected to be 8% each. The expected price of sugar on January 1, 1996 would be
Price of sugar on January 1, 1996 = 20 [ 1 + 10/100]^2 = 20 x 1.21 = 24.20 Rs
Q started to move from point B towards point A exactly an hour after P started from A in the opposite direction. Q’s speed was twice that of P. When P had covered one-sixth of the distance between the points A and B, Q had also covered the same distance. The point where P and Q would meet is
(a) Closer to A
(b) Exactly between A and B
(c) Closer to B
(d) P and Q will not meet at all
Let the total distance be d.
After each covering 1/6 of the total distance, P and Q has a distance of (d - d/6 - d/6) = 2d/3 between them.
Q moves at 2S and P moves at S.
distance covered by Q will be double that by P once they meet
So Q travels 4d/9 and P travels 2d/9
Meeting point will be closer to A
In the above question, how many hours would P take to reach B?
Time for covering 1/6th of total distance,
For P = (d/6) / S
For Q = [ (d/6) / (2S)] + 1
d/6S - d/12S = 1
d = 12S
So for P will take 12S/S = 12 hours to cover the whole distance.