Answer: 15/24 + 6/24 = 21/24
Explanation
when you put the new denominator (which is 28 on both fractions) you have to multiply the numerator by how many times it takes the denominator. example. 5/8 8 can go into 24, 3 times so u multiply
5 by 3 same with the other side just u multiply 3 by 2