Answer:
15
Step-by-step explanation:
y/x=constant
20/4=y/3
y=5*3
y=15
3x +x = 28
4x = 28
x = 28/4 = 7
7x3 = 21
Sari has 21 erasers
40 * 6.5 = 260 --> D. 260.00
5x is the missing term