Tank N contained 2 times as many guppies as Tank P. When 10% of the guppies in Tank N and 40% of the guppies in Tank P were transferred to Tank Q, Tank Q had 60 guppies, which was 25% 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	2 u	1 u	4x0.6 = 2.4 u
Change	- 0.2 u	- 0.4 u	+ 1x0.6 = + 0.6 u
After	1.8 u	0.6 u	5x0.6 = 3 u

Number of guppies that were transferred from Tank N to Tank Q
= 10% x 2 u
= ¹⁰₁₀₀ x 2 u
= 0.2 u

Number of guppies that were transferred from Tank P to Tank Q
= 40% x 1 u
= ⁴⁰₁₀₀ x 1 u
= 0.4 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
= 0.2 u + 0.4 u
= 0.6 u

3 u = 60

1 u = 60 ÷ 3 = 20

Number of less guppies in Tank P than Tank N
= 1.8 u - 0.6 u
= 1.2 u
= 1.2 x 20
= 24

Answer(s): 24