Final answer:
The student wants 60% of 20 cupcakes, which is 12 cupcakes.
Step-by-step explanation:
If the student initially wanted to buy 20 cupcakes and now wants only 60% of that amount, we can calculate the number they wish to now purchase by taking 60 percent of 20. To do this, you multiply 20 by 0.60 (since 60% is equal to 0.60 in decimal form). Therefore, 20 × 0.60 = 12. This means the student would like to buy 12 cupcakes instead of the initial 20 to adhere to their doctor's health advice.