Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 山姆的年龄是苏的两倍。肯德拉的年龄是山姆的三倍。如果肯德拉现在18岁，三年后他们的总年龄是多少？


### Response:
 肯德拉的年龄是山姆的三倍，所以3 * 18 = <<3*18=54>>54
山姆的年龄是苏的两倍，所以54 / 2 = <<54/2=27>>27
苏是27岁，肯德拉是54岁，山姆是27岁，总年龄是27 + 54 + 27 = <<27+54+27=108>>108
三年后，肯德拉将是21岁，山姆将是30岁，苏将是30岁，总年龄是21 + 30 + 30 = <<21+30+30=81>>81