Quantitative Aptitude - Arithmetic Ability Questions

rate=r%

1200 (1+r/100)^2=1348.32

r=6%

x / y  = 0.04 / 1.5 = 4 / 150 = 2 / 75.

= > ( (y - x) / (y+x) ) = (1 - (x / y)) / ( 1 + ( x / y)) = (1 - 2/75) / (1 + 2/75) = 73/77...

Less Men, means more Days {Indirect Proportion}

Let the number of days be x then,

27 : 36 :: 18 : x

[Please pay attention, we have written 27 : 36 rather than 36 : 27, in indirect proportion, if you get it then chain rule is clear to you :)]                                

=>27x = 36 * 18

=> x = 24

 So 24 days will be required to get work done by 27 men.

There are 7 digits 1, 2, 0, 2, 4, 2, 4 in which 2 occurs 3 times, 4 occurs 2 times.

 Number of 7 digit numbers = 7!3!×2! = 420

But out of these 420 numbers, there are some numbers which begin with '0' and they are not 7-digit numbers. The number of such numbers beginning with '0'.

=6!3!×2! = 60

Hence the required number of 7 digits numbers = 420 - 60 = 360