Andy had some banana biscuits and apricot biscuits. ³₇ of the number of banana biscuits was equal to ¹₇ of the number of apricot biscuits. After Andy made 231 more banana biscuits, the number of banana biscuits was ⁴₃ of the number of apricot biscuits. How many biscuits did he have altogether in the end?
Make the numerators the same. LCM of 3 and 1 is 3.

37 of banana biscuits = 1x37x3 of apricot biscuits

³₇ of banana biscuits = ³₂₁ of apricot biscuits

	Banana biscuits	Apricot biscuits	Total
Before	7 u	21 u
Change	+ 231
After	4x7 = 28 u	3x7 = 21 u	49 u

The number of apricot biscuits remains unchanged.  Make the number of apricot biscuits the same.  LCM of 3 and 21 is 21.

Number of more banana biscuits made
= 28 u - 7 u
= 21 u

21 u = 231

1 u = 231 ÷ 21 = 11

Number of biscuits that Andy had in the end
= 28 u + 21 u
= 49 u
= 49 x 11
= 539

Answer(s): 539