Tank P contained 3 times as many guppies as Tank Q. When 10% of the guppies in Tank P and 40% of the guppies in Tank Q were transferred to Tank R, Tank R had 105 guppies, which was 25% more guppies than before. How many less guppies were there in Tank Q than Tank P in the end?

	Tank P	Tank Q	Tank R
Before	3 u	1 u	4x0.7 = 2.8 u
Change	- 0.3 u	- 0.4 u	+ 1x0.7 = + 0.7 u
After	2.7 u	0.6 u	5x0.7 = 3.5 u

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

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

25% = ²⁵₁₀₀ = ¹₄

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

Total number of guppies transferred from Tank P and Tank Q into Tank R
= 0.3 u + 0.4 u
= 0.7 u

3.5 u = 105

1 u = 105 ÷ 3.5 = 30

Number of less guppies in Tank Q than Tank P
= 2.7 u - 0.6 u
= 2.1 u
= 2.1 x 30
= 63

Answer(s): 63