Subject: mathqa
Question: the prices of tea and coffee per kg were the same in june . in july the price of coffee shot up by 20 % and that of tea dropped by 20 % . if in july , a mixture containing equal quantities of tea and coffee costs 70 / kg . how much did a kg of coffee cost in june ?
Option: 
A: 80
B: 70
C: 100
D: 60
Answer: B