Tank V contained 2 times as many guppies as Tank W. When 40% of the guppies in Tank V and 20% of the guppies in Tank W were transferred to Tank X, Tank X had 150 guppies, which was 25% more guppies than before. How many more guppies were there in Tank X than Tank W in the end?

	Tank V	Tank W	Tank X
Before	2 u	1 u	4x1 = 4 u
Change	- 0.8 u	- 0.2 u	+ 1x1 = + 1 u
After	1.2 u	0.8 u	5x1 = 5 u

Number of guppies that were transferred from Tank V to Tank X
= 40% x 2 u
= ⁴⁰₁₀₀ x 2 u
= 0.8 u

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

25% = ²⁵₁₀₀ = ¹₄

Some guppies from Tank V and Tank W were transferred to Tank X.  The total number of guppies transferred from Tank V and Tank W into Tank X is the same.

Total number of guppies transferred from Tank V and Tank W into Tank X
= 0.8 u + 0.2 u
= 1 u

5 u = 150

1 u = 150 ÷ 5 = 30

Number of more guppies in Tank X than Tank W
= 5 u - 0.8 u
= 4.2 u
= 4.2 x 30
= 126

Answer(s): 126