Blue shirts = B
Yellow shirts = Y
Total shirts = T
![T=B+Y](https://img.qammunity.org/2023/formulas/mathematics/college/8cbwsnhk3fyyu4otimteza5xw9gfwa63l3.png)
For every 3B there are 5Y
![3B=5Y](https://img.qammunity.org/2023/formulas/mathematics/college/y95hvynvtkj6jc2gjutr93copl95ie07r2.png)
Then we clear a variable of one of the equations:
In 3B = 5Y
![B=(5)/(3)Y](https://img.qammunity.org/2023/formulas/mathematics/college/vb2eg354vgi4309qn0ehopkj6dt5zjyogn.png)
We use this in the equation T = B + Y with T=72
![72=(5)/(3)Y+Y](https://img.qammunity.org/2023/formulas/mathematics/college/my2rs4x5bht1044u89n1u8sfkfyuod9lr8.png)
We clear the Y:
![72=(8)/(3)Y](https://img.qammunity.org/2023/formulas/mathematics/college/u41edenxxovtwauyxonwvx7jrsp8u24c0o.png)
![72\cdot(3)/(8)=Y](https://img.qammunity.org/2023/formulas/mathematics/college/80ir9ye91l12zv2da7tq7sa2o11ju7hm95.png)
![Y=27](https://img.qammunity.org/2023/formulas/mathematics/college/avt8nhf1i0suf4e1ns4lx7xhndo2ofywdm.png)
We use this value of Y in the equation 3B=5Y to know the B:
![3B=5(27)](https://img.qammunity.org/2023/formulas/mathematics/college/6bfamdjtz9gdun2eedfrm8qgtvu3opx442.png)
![B=(135)/(3)=45](https://img.qammunity.org/2023/formulas/mathematics/college/wftwhas106roaxmovangfiz6vzx3vjcaqm.png)
Then so, the number of shirts is:27 yellow shirts and 45 Blue shirts