Tank K contained 4 times as many guppies as Tank L. When 40% of the guppies in Tank K and 30% of the guppies in Tank L were transferred to Tank M, Tank M had 171 guppies, which was 50% 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	4 u	1 u	2x1.9 = 3.8 u
Change	- 1.6 u	- 0.3 u	+ 1x1.9 = + 1.9 u
After	2.4 u	0.7 u	3x1.9 = 5.7 u

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

Number of guppies that were transferred from Tank L to Tank M
= 30% x 1 u
= ³⁰₁₀₀ x 1 u
= 0.3 u

50% = ⁵⁰₁₀₀ = ¹₂

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
= 1.6 u + 0.3 u
= 1.9 u

5.7 u = 171

1 u = 171 ÷ 5.7 = 30

Number of less guppies in Tank L than Tank K
= 2.4 u - 0.7 u
= 1.7 u
= 1.7 x 30
= 51

Answer(s): 51