The total weight of the shape blocks on both sides of Kim's pan balance equals 30 grams. Circles weigh 5 grams, squares weigh 10 grams, and triangles weigh 3 grams. The right side has circle and square. How many triangles are on the left side?
A) 5
B) 4
C) 6
D) 10
Answer is 5. Please check. Thank you