Aptitude - Chain Rule

Let the height of the building x metres.

Less lengthy shadow, Less in the height (Direct Proportion)

40.25 : 28.75 :: 17.5 : x       40.25 x x = 28.75 x 17.5

x = 12.5

There is a meal for 200 children. 150 children have taken the meal.

Remaining meal is to be catered to 50 children.

Now, 200 children 120 men.

50 children		120	x 50		= 30 men.
		200

Le the required time be x seconds.

More metres, More time (Direct Proportion)

0.128 : 25 :: 1 : x       0.128x = 25 x 1

x = 195.31.

Required time = 195 sec (approximately).

Let the required number of days be x.

Less men, More days (Indirect Proportion)

27 : 36 :: 18 : x       27 x x = 36 x 18

x =	36 x 18
	27

x = 24.

Let the required number of bottles be x.

More weavers, More mats (Direct Proportion)

More days, More mats (Direct Proportion)

Wavers	4	:	8		:: 4 : x
Days	4	:	8

4 x 4 x x = 8 x 8 x 4

x =	(8 x 8 x 4)
	(4 x 4)

x = 16.