Tank L contained 2 times as many guppies as Tank M. When 20% of the guppies in Tank L and 40% of the guppies in Tank M were transferred to Tank N, Tank N had 96 guppies, which was 20% more guppies than before. How many more guppies were there in Tank N than Tank M in the end?

	Tank L	Tank M	Tank N
Before	2 u	1 u	5x0.8 = 4 u
Change	- 0.4 u	- 0.4 u	+ 1x0.8 = + 0.8 u
After	1.6 u	0.6 u	6x0.8 = 4.8 u

Number of guppies that were transferred from Tank L to Tank N
= 20% x 2 u
= ²⁰₁₀₀ x 2 u
= 0.4 u

Number of guppies that were transferred from Tank M to Tank N
= 40% x 1 u
= ⁴⁰₁₀₀ x 1 u
= 0.4 u

20% = ²⁰₁₀₀ = ¹₅

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

Total number of guppies transferred from Tank L and Tank M into Tank N
= 0.4 u + 0.4 u
= 0.8 u

4.8 u = 96

1 u = 96 ÷ 4.8 = 20

Number of more guppies in Tank N than Tank M
= 4.8 u - 0.6 u
= 4.2 u
= 4.2 x 20
= 84

Answer(s): 84