Answers Week 4

Logical 6 - Number Test

If it is possible to make a number which is perfect square of a two digit odd number with the second, the sixth and the ninth digits of the number 187642539, which of the following is the digit in the unit's place of that two-digit odd number?

The second, sixth and ninth digits of the number 1876425339 are 8, 2 and 9 respectively.

The perfect square of the two digit odd number formed using the digits 8, 2 and 9 is 289 and 289 = 17². 

So, the required odd number is 17 and the digit in the unit's place is 7.


Logical 7 - Statements and Assumptions

"I have not received telephone bills for nine months inspite of several complaints" - A telephone customer's letter to the editor of a daily.

Assumptions - 
I. Every customer has a right to get bills regularly from the telephone company.
II. The customer's complaints point to defect in the services which is expected to be corrected.

The customer's eagerness to get the bills makes I implicit.
Besides, the customer has written to the editor to bring the malfunctioning of the department to public notice.
So, II is also implicit.
Hence, answer is (e) - both I and II are implicit.


Quants 8 - Percentage

(i) 1/2 is what % of 1/3?

(ii) What % of 6.5 litres is 130 ml?

(i) (1/2) * 100 * (1/3) = 150%

(ii) 130 / (6.5 * 1000) * 100 = 2%

Quants 9 - Problem om Trains

A train 220 m long is running with a speed of 59 kmph. In what time will it pass a man who is running at 7 kmph in the direction opposite to that in which the train is going?

Speed of the train relative to man = 59 + 7 = 66 kmph = 66 * (5/18) = 55/3 m/s

Time taken by the train to cross the man = Time taken by it to cover 220 m at 55/3 m/s

=> 220 * (3/55) = 12 sec


Quants 10 - Average

If a, b, c, d and e are five odd consecutive numbers, their average is ___.

Clearly, b = a + 2,

c = a + 4

d = a + 6

e = a + 8

Average = ( a + (a+2) + (a+4) + (a+6) + (a+8) ) / 5 

( 5a + 20 ) / 5

a + 4