The number of mandarin oranges Liam bought in October was 25% more than in September. In November, he bought 50% less mandarin oranges than in October. If there were 9 more mandarin oranges in September than November, how many mandarin oranges did Liam buy in September?

September	October	November
4x2	5x2
	2x5	1x5
8 u	10 u	5 u

100% + 25 = 125%
125% = ¹²⁵₁₀₀ = ⁵₄
October : September = 5 : 4 

100% - 50% = 50%
50% = ⁵⁰₁₀₀ = ¹₂
November : October = 1 : 2

The number of mandarin oranges in October is repeated.  Make the number of mandarin oranges in October is the same.  LCM of 5 and 2 is 10.

Number of more mandarin oranges in September than November
= 8 u - 5 u
= 3 u

3 u = 9

1 u = 9 ÷ 3 = 3

Number of mandarin oranges that Liam bought in September
= 8 u
= 8 x 3
= 24

Answer(s): 24