The number of grapefruits Simon bought in October was 30% more than in September. In November, he bought 60% less grapefruits than in October. If there were 168 more grapefruits in September than November, how many grapefruits did Simon buy in September?

September	October	November
10x5	13x5
	5x13	2x13
50 u	65 u	26 u

100% + 30 = 130%
130% = ¹³⁰₁₀₀ = ¹³₁₀
October : September = 13 : 10 

100% - 60% = 40%
40% = ⁴⁰₁₀₀ = ²₅
November : October = 2 : 5

The number of grapefruits in October is repeated.  Make the number of grapefruits in October is the same.  LCM of 13 and 5 is 65.

Number of more grapefruits in September than November
= 50 u - 26 u
= 24 u

24 u = 168

1 u = 168 ÷ 24 = 7

Number of grapefruits that Simon bought in September
= 50 u
= 50 x 7
= 350

Answer(s): 350