Tank Q contained 4 times as many guppies as Tank R. When 40% of the guppies in Tank Q and 20% of the guppies in Tank R were transferred to Tank S, Tank S had 54 guppies, which was 50% more guppies than before. How many less guppies were there in Tank R than Tank Q in the end?

	Tank Q	Tank R	Tank S
Before	4 u	1 u	2x1.8 = 3.6 u
Change	- 1.6 u	- 0.2 u	+ 1x1.8 = + 1.8 u
After	2.4 u	0.8 u	3x1.8 = 5.4 u

Number of guppies that were transferred from Tank Q to Tank S
= 40% x 4 u
= ⁴⁰₁₀₀ x 4 u
= 1.6 u

Number of guppies that were transferred from Tank R to Tank S
= 20% x 1 u
= ²⁰₁₀₀ x 1 u
= 0.2 u

50% = ⁵⁰₁₀₀ = ¹₂

Some guppies from Tank Q and Tank R were transferred to Tank S.  The total number of guppies transferred from Tank Q and Tank R into Tank S is the same.

Total number of guppies transferred from Tank Q and Tank R into Tank S
= 1.6 u + 0.2 u
= 1.8 u

5.4 u = 54

1 u = 54 ÷ 5.4 = 10

Number of less guppies in Tank R than Tank Q
= 2.4 u - 0.8 u
= 1.6 u
= 1.6 x 10
= 16

Answer(s): 16