Quantitative Aptitude - Arithmetic Ability Questions

Given,721+722+723+724

721(1 + 7 + 49 + 343)
721(400)

Now, 400 is divisible by 25. The remainder will be 0

Ratio of length and breadth is 6 : 5
∴ Length = 6x
Breadth = 5x
∴ Area = l x b = 30x2
∴ Perimeter = 2 (l + b) = 2(6x + 5x) =22x
∴ (30*x*x)/(22x)= 60/11
∴ X = 4
∴ Length = 6x = 6 x 4 = 24 units

As A1 speaks always after A2, they can speak only in  1st  to 9th places and 

A2 can speak in 2nd to 10 the places only when A1 speaks in 1st place 

A2 can speak in 9 places the remaining 

 A3, A4, A5,...A10  has no restriction. So, they can speak in 9.8! ways. i.e

when A2 speaks in the first place, the number of ways they can speak is 9.8!.

When A2 speaks in second place, the number of ways they can speak is  8.8!.

When A2 speaks in third place, the number of ways they can speak is  7.8!. When A2 speaks in the ninth place, the number of ways they can speak is 1.8!

Therefore,Total Number of ways they can  speak = (9+8+7+6+5+4+3+2+1) 8! = 92(9+1)8! = 10!/2

Ratio of times taken by A and B = 160 : 100
A can do the work in 12 days
Let B can do the work in "D" days
=> 160:100 = 12 : D
=> D = 12 x 100/160 = 7.5 hrs

i=j/m

n
=m(Term)
= 2(15.5)
=31

Fair market value
Present value of the face value

=FV(1+  i)^-n

Suppose that the original price of the car = Rs. x 

Then new price of the car

=> (x) + (x ×25/100) = Rs. 5x/4 

To restore the original price, the new price must be decreased by

5x/4 − x = x/4

So required percentage =(x/4)/(5x/4) × 100%

= 20%