Answer:
30
Explanation:
For the minimum free throws, he must put every throw to the basket.
So, let n be the number of throws for Tuesday, in which all the throws are successful.
So, over both the days, total free throws he makes= 15+n.
Total numbers of throws that went in the basket= 6+n.
As he wants at least 80% of his balls to go in the basket.
So, 6+n is greater than or equal to 809% of 15+n, i.e
![6+n\geq (80)/(100)* (15+n)](https://img.qammunity.org/2021/formulas/mathematics/high-school/xnu1u9fmskzv7v002kj7nd81a60xtt4fak.png)
![\Rightarrow 30+5n\geq 60+4n](https://img.qammunity.org/2021/formulas/mathematics/high-school/7d0kry16x8vnjjvmnxygqc16rlskexk05r.png)
![\Rightarrow n\geq 30.](https://img.qammunity.org/2021/formulas/mathematics/high-school/l0vm4jkwcvla32dxy1yfaoyd1e2fjfge8s.png)
Hence, the minimum number of free throws required on Tuesday to reach his goal is 30.