PSLE
Anna had rubik's cubes for sale. In the morning, she sold ³₈ of the rubik's cubes. In the afternoon, she sold ³₁₀ of the remaining rubik's cubes. After that, there were 84 rubik's cubes left. How many rubik's cubes did Anna have at first?
Fraction of rubik's cubes left after selling in the morning
= 1 - ³₈
= ⁵₈

Fraction of the remaining rubik's cubes after selling in the afternoon
= 1 - ³₁₀
= ⁷₁₀

⁷₁₀ of remaining rubik's cubes = 84
¹₁₀ of remaining rubik's cubes = 84 ÷ 7 = 12
¹⁰₁₀ of remaining rubik's cubes = 10 x 12 = 120

⁵₈ of total rubik's cubes = 120
³₈ of the total rubik's cubes = 120 ÷ 5 = 24
⁸₈ of the total rubik's cubes = 8 x 24 = 192

Number of rubik's cubes at first = 192

Answer(s): 192