Assistant Director FIA (2020)

= (1000)⁹÷  (10)²⁴

= (10³)⁹ ÷  (10)²⁴   

= 10²⁷ ÷  (10)²⁴   

= 10^27-24

= 10³

⁼ 1000

Let the father’s age be x and the son’s age be y.

Then, x – y = y or x = 2y,

Now, x = 36. So, 2y = 36 or y = 18.

Therefore Son’s present age = 18 years.

So, son’s age 5 years ago = 13 years

2 + 3 =5 

5 + 7 =12

12 +11 =23

23 + 15= 38

38 + 19 = 57

57 + 23 = 80

3 x 3 =9 – 3= 6

6 x 3 = 18-3 = 15

15 x 3= 45 – 3=42

42 x 3 = 126 – 3 = 123

123 x 3 = 369 – 3 = 366

Let,
Cost Price (CP) = Rs. 100
Profit % = 20
Selling Price (SP) = 120

When profit increases from 20% to 25%
Cost Price (CP) = y
Profit % = 25
Selling Price (SP) after 25% increase = 120 + 25% = Rs. 150


From question
y + 25 % profit = 150

1.25 y = 150
so y = 120

% change in cost price = [ (120 – 100) / 100 ] x 100 = 20%

let sequence=x, x+2, x+4, x+6
sum of sequence=4x+12
if 4x+12 is a multiple of 10,
then x must have a units digit of 7
4*17+12=80; 80/10=8 no
4*27+12=120; 120/10=12 no
4*37+12=160; 160/10=16 yes
sequence=37, 39, 41, 43

10 men can do work = 12 days 

1 men can do this work = 12 x 10 = 120 days

12 men will do this work= 120/12= 10 days 

Using Flip rule:

A and B complete work in = 15 days
One day’s work of (A + B) = 1/15

B complete the work in = 20 days;
One day’s work of B = 1/20 

Then, A’s one day’s work

Thus, A can complete the work in = 60 days.