Final answer:
To determine the number of balls in the basket that are not tennis balls, subtract the number of tennis balls (9) from the total number of balls (18), resulting in 9 balls that are not tennis balls.
Step-by-step explanation:
If there are 18 balls in a basket and nine of them are tennis balls, the remainder will not be tennis balls. To find out how many balls are not tennis balls, we need to subtract the number of tennis balls from the total number of balls.
Here's the calculation:
- Total number of balls in the basket: 18
- Number of tennis balls: 9
- Number of balls that are not tennis balls = Total number of balls − Number of tennis balls = 18 − 9
- Number of balls that are not tennis balls = 9
Therefore, there are 9 balls in the basket that are not tennis balls.