PSLE
Elyse had rubik's cubes for sale. In the morning, she sold ¹₅ of the rubik's cubes. In the afternoon, she sold ³₈ of the remaining rubik's cubes. After that, there were 85 rubik's cubes left. How many rubik's cubes did Elyse have at first?
Fraction of rubik's cubes left after selling in the morning
= 1 - ¹₅
= ⁴₅

Fraction of the remaining rubik's cubes after selling in the afternoon
= 1 - ³₈
= ⁵₈

⁵₈ of remaining rubik's cubes = 85
¹₈ of remaining rubik's cubes = 85 ÷ 5 = 17
⁸₈ of remaining rubik's cubes = 8 x 17 = 136

⁴₅ of total rubik's cubes = 136
¹₅ of the total rubik's cubes = 136 ÷ 4 = 34
⁵₅ of the total rubik's cubes = 5 x 34 = 170

Number of rubik's cubes at first = 170

Answer(s): 170