Tank S contained 2 times as many guppies as Tank T. When 10% of the guppies in Tank S and 40% of the guppies in Tank T were transferred to Tank U, Tank U had 72 guppies, which was 50% more guppies than before. How many less guppies were there in Tank T than Tank S in the end?

	Tank S	Tank T	Tank U
Before	2 u	1 u	2x0.6 = 1.2 u
Change	- 0.2 u	- 0.4 u	+ 1x0.6 = + 0.6 u
After	1.8 u	0.6 u	3x0.6 = 1.8 u

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

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

50% = ⁵⁰₁₀₀ = ¹₂

Some guppies from Tank S and Tank T were transferred to Tank U.  The total number of guppies transferred from Tank S and Tank T into Tank U is the same.

Total number of guppies transferred from Tank S and Tank T into Tank U
= 0.2 u + 0.4 u
= 0.6 u

1.8 u = 72

1 u = 72 ÷ 1.8 = 40

Number of less guppies in Tank T than Tank S
= 1.8 u - 0.6 u
= 1.2 u
= 1.2 x 40
= 48

Answer(s): 48