Tank N contained 4 times as many guppies as Tank P. When 20% of the guppies in Tank N and 20% of the guppies in Tank P were transferred to Tank Q, Tank Q had 60 guppies, which was 20% more guppies than before. How many less guppies were there in Tank P than Tank N in the end?

	Tank N	Tank P	Tank Q
Before	4 u	1 u	5x1 = 5 u
Change	- 0.8 u	- 0.2 u	+ 1x1 = + 1 u
After	3.2 u	0.8 u	6x1 = 6 u

Number of guppies that were transferred from Tank N to Tank Q
= 20% x 4 u
= ²⁰₁₀₀ x 4 u
= 0.8 u

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

20% = ²⁰₁₀₀ = ¹₅

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

Total number of guppies transferred from Tank N and Tank P into Tank Q
= 0.8 u + 0.2 u
= 1 u

6 u = 60

1 u = 60 ÷ 6 = 10

Number of less guppies in Tank P than Tank N
= 3.2 u - 0.8 u
= 2.4 u
= 2.4 x 10
= 24

Answer(s): 24