Tank K contained 3 times as many guppies as Tank L. When 20% of the guppies in Tank K and 20% of the guppies in Tank L were transferred to Tank M, Tank M had 144 guppies, which was 20% more guppies than before. How many less guppies were there in Tank L than Tank K in the end?

	Tank K	Tank L	Tank M
Before	3 u	1 u	5x0.8 = 4 u
Change	- 0.6 u	- 0.2 u	+ 1x0.8 = + 0.8 u
After	2.4 u	0.8 u	6x0.8 = 4.8 u

Number of guppies that were transferred from Tank K to Tank M
= 20% x 3 u
= ²⁰₁₀₀ x 3 u
= 0.6 u

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

20% = ²⁰₁₀₀ = ¹₅

Some guppies from Tank K and Tank L were transferred to Tank M.  The total number of guppies transferred from Tank K and Tank L into Tank M is the same.

Total number of guppies transferred from Tank K and Tank L into Tank M
= 0.6 u + 0.2 u
= 0.8 u

4.8 u = 144

1 u = 144 ÷ 4.8 = 30

Number of less guppies in Tank L than Tank K
= 2.4 u - 0.8 u
= 1.6 u
= 1.6 x 30
= 48

Answer(s): 48