Tank N contained 3 times as many guppies as Tank P. When 10% of the guppies in Tank N and 20% of the guppies in Tank P were transferred to Tank Q, Tank Q had 25 guppies, which was 25% more guppies than before. How many more guppies were there in Tank Q than Tank P in the end?

	Tank N	Tank P	Tank Q
Before	3 u	1 u	4x0.5 = 2 u
Change	- 0.3 u	- 0.2 u	+ 1x0.5 = + 0.5 u
After	2.7 u	0.8 u	5x0.5 = 2.5 u

Number of guppies that were transferred from Tank N to Tank Q
= 10% x 3 u
= ¹⁰₁₀₀ x 3 u
= 0.3 u

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

25% = ²⁵₁₀₀ = ¹₄

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
= 0.3 u + 0.2 u
= 0.5 u

2.5 u = 25

1 u = 25 ÷ 2.5 = 10

Number of more guppies in Tank Q than Tank P
= 2.5 u - 0.8 u
= 1.7 u
= 1.7 x 10
= 17

Answer(s): 17