Answer: 36 problems
Explanation:
40% is nothing but 40/100, which is just 4/10. To start, multiply 60 by the fraction 4/10. Cancel out the 10 from the denominator of the fraction to get 4 x 6 = 24. Now, we just found the number of problems that the student solved, but we need to find how many problems still need to be solved. To do that, do 60 - 24 = 36. The student needs to solve 36 more problems.
I hope this helps!