Tank R contained 4 times as many guppies as Tank S. When 50% of the guppies in Tank R and 10% of the guppies in Tank S were transferred to Tank T, Tank T had 252 guppies, which was 50% more guppies than before. How many less guppies were there in Tank S than Tank R in the end?

	Tank R	Tank S	Tank T
Before	4 u	1 u	2x2.1 = 4.2 u
Change	- 2 u	- 0.1 u	+ 1x2.1 = + 2.1 u
After	2 u	0.9 u	3x2.1 = 6.3 u

Number of guppies that were transferred from Tank R to Tank T
= 50% x 4 u
= ⁵⁰₁₀₀ x 4 u
= 2 u

Number of guppies that were transferred from Tank S to Tank T
= 10% x 1 u
= ¹⁰₁₀₀ x 1 u
= 0.1 u

50% = ⁵⁰₁₀₀ = ¹₂

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

Total number of guppies transferred from Tank R and Tank S into Tank T
= 2 u + 0.1 u
= 2.1 u

6.3 u = 252

1 u = 252 ÷ 6.3 = 40

Number of less guppies in Tank S than Tank R
= 2 u - 0.9 u
= 1.1 u
= 1.1 x 40
= 44

Answer(s): 44