单选题 A sub sandwich and a soda at a basketball game's concession stand costs $3.40. A family purchases three sub sandwiches and two sodas, and the total cost is $9.10. What is the cost of a soda?

A. $1.00
B. $1.10
C. $1.15
D. $1.20
E. $1.40

【正确答案】 B

【答案解析】The problem can be solved by using two simultaneous equations: s+d=3.40 and 3s+2d=9.10. Doubling the first equation and subtracting it from the second gives the result that s (the cost of a soda) is $1.10.