克拉伦斯、阿米尔和俊伟收到了一些贴纸。克拉伦斯收到的贴纸数量与阿米尔收到的贴纸数量之比为 4 : 9。俊伟收到的贴纸数量与阿米尔收到的贴纸数量之比为 4 : 3。克拉伦斯收到了 24 张贴纸。俊伟收到了多少张贴纸？ 答：___

1. Find a common ratio for Clarence, Amir, and Jun Wei by making Amir's units the same.

We are given:
Ratio of Clarence to Amir, $C : A = 4 : 9$
Ratio of Jun Wei to Amir, $J : A = 4 : 3$

To combine them, we make the parts for Amir ($A$) the same. The lowest common multiple of 9 and 3 is 9.
$J : A = 4 : 3 = (4 \times 3) : (3 \times 3) = 12 : 9$

Now we can combine them into a single ratio:
$C : A : J = 4 : 9 : 12$

2. Calculate the number of stickers Jun Wei received using the unified ratio.

Clarence received 24 stickers, which corresponds to 4 units.
$4\text{ units} = 24$
$1\text{ unit} = \frac{24}{4} = 6$

Jun Wei's share corresponds to 12 units:
$\text{Number of stickers Jun Wei received} = 12 \times 6 = 72$