Tank G contained 3 times as many guppies as Tank H. When 10% of the guppies in Tank G and 30% of the guppies in Tank H were transferred to Tank J, Tank J had 90 guppies, which was 25% more guppies than before. How many less guppies were there in Tank H than Tank G in the end?

	Tank G	Tank H	Tank J
Before	3 u	1 u	4x0.6 = 2.4 u
Change	- 0.3 u	- 0.3 u	+ 1x0.6 = + 0.6 u
After	2.7 u	0.7 u	5x0.6 = 3 u

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

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

25% = ²⁵₁₀₀ = ¹₄

Some guppies from Tank G and Tank H were transferred to Tank J.  The total number of guppies transferred from Tank G and Tank H into Tank J is the same.

Total number of guppies transferred from Tank G and Tank H into Tank J
= 0.3 u + 0.3 u
= 0.6 u

3 u = 90

1 u = 90 ÷ 3 = 30

Number of less guppies in Tank H than Tank G
= 2.7 u - 0.7 u
= 2 u
= 2 x 30
= 60

Answer(s): 60