Tank M contained 4 times as many guppies as Tank N. When 50% of the guppies in Tank M and 30% of the guppies in Tank N were transferred to Tank P, Tank P had 138 guppies, which was 50% more guppies than before. How many more guppies were there in Tank P than Tank N in the end?

	Tank M	Tank N	Tank P
Before	4 u	1 u	2x2.3 = 4.6 u
Change	- 2 u	- 0.3 u	+ 1x2.3 = + 2.3 u
After	2 u	0.7 u	3x2.3 = 6.9 u

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

Number of guppies that were transferred from Tank N to Tank P
= 30% x 1 u
= ³⁰₁₀₀ x 1 u
= 0.3 u

50% = ⁵⁰₁₀₀ = ¹₂

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

Total number of guppies transferred from Tank M and Tank N into Tank P
= 2 u + 0.3 u
= 2.3 u

6.9 u = 138

1 u = 138 ÷ 6.9 = 20

Number of more guppies in Tank P than Tank N
= 6.9 u - 0.7 u
= 6.2 u
= 6.2 x 20
= 124

Answer(s): 124