Let 5 M&M candies and 3 Starbursts candies be referred to as the unit amounts of each candy.
5 M&M candies make one unit so 25 makes 25/5 = <<25/5=5>>5 units of M&M candies
For every unit of 5 M&M candies, there is a corresponding unit of 3 Starbursts candies so for 5 units of M&M, she has 5 units of 3 Starbursts candies which is = 5*3 = <<5*3=15>>15 Starbursts candies.
#### 15