Kalon has $80 saved. He earns $115 a week and spends $75 each week on gas and groceries. He plans to buy new tires for his car in 6 weeks that cost $140. How much should he plan to save each week?
A. $15
B. $20
C. $10
D. $12
115-75 = 40
80 + 6x = 160