Question

i want a total of 20 cupcakes, thank you very much. some should be sunrise, and the rest, exactly 90% should be yum - yum.

Explanation:

Step1: Find number of Yum - Yum cupcakes

We know that the total number of cupcakes is 20 and 90% of them are Yum - Yum. To find the number of Yum - Yum cupcakes, we calculate 90% of 20. The formula for finding a percentage of a number is $n=\text{percentage}\times\text{total number}$, where the percentage is in decimal form. 90% in decimal form is 0.9. So, the number of Yum - Yum cupcakes $y = 0.9\times20=18$.

Step2: Find number of Sunrise cupcakes

The total number of cupcakes is 20, and the number of Yum - Yum cupcakes is 18. Let the number of Sunrise cupcakes be $s$. We know that $s + y=20$. Substituting the value of $y$ we found, we get $s=20 - 18 = 2$.

Answer:

Number of Yum - Yum cupcakes is 18 and number of Sunrise cupcakes is 2. So we need to select 18 Yum - Yum and 2 Sunrise cupcakes.