Tank P contained 4 times as many guppies as Tank Q. When 10% of the guppies in Tank P and 30% 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 more guppies were there in Tank R than Tank Q in the end?

	Tank P	Tank Q	Tank R
Before	4 u	1 u	4x0.7 = 2.8 u
Change	- 0.4 u	- 0.3 u	+ 1x0.7 = + 0.7 u
After	3.6 u	0.7 u	5x0.7 = 3.5 u

Number of guppies that were transferred from Tank P to Tank R
= 10% x 4 u
= ¹⁰₁₀₀ x 4 u
= 0.4 u

Number of guppies that were transferred from Tank Q to Tank R
= 30% x 1 u
= ³⁰₁₀₀ x 1 u
= 0.3 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
= 0.4 u + 0.3 u
= 0.7 u

3.5 u = 105

1 u = 105 ÷ 3.5 = 30

Number of more guppies in Tank R than Tank Q
= 3.5 u - 0.7 u
= 2.8 u
= 2.8 x 30
= 84

Answer(s): 84