Suggested answer:

Cost of 1 file = cost of 2 erasers

Cost of 5 file = cost of 10 erasers

25% of her money –> 20 erasers

40% of (100% – 25% )=  30%

20 erasers/ 25% x 30% = 24 erasers

24 + 10 = 34

Ans: She bought 34 erasers in total