What is the value of the expression below?

- 8/15 + (- 3/10) + 8/15 + 10/3

a) 0

b) 13/10

c) 91/30

d) 109/30

The answer is C) 91/30
This is how it is done: you will have to find common number and equalize the denominators I mean the common number of 3, 10 and 15 is 30. So when you multiply the denominator with a number you will have to multiply the numerator to the same number for example : -8/15 ( you will multiply it by 2 to get 30 for the denominator ) so it becomes -16/30 . And then you equalize the rest and do the operations simply but you won't add or subtract the denominators you will only add and subtract the numerators ( don't make mistakes in multiplication cuz it's different ). Let me know if you want any additional information And i will do my best

How many groups are there?

Need the graph to answer this.