Answer:
![Total = 72\ km](https://img.qammunity.org/2022/formulas/mathematics/college/v7c39svypj6iw2trpgt773kytbz7xwetb9.png)
Explanation:
Given
![Fly = (3)/(4)](https://img.qammunity.org/2022/formulas/mathematics/college/ypuacxss36uxb82a6kcw1ne429ks73qjdx.png)
![Walk = (1)/(9)](https://img.qammunity.org/2022/formulas/mathematics/college/2jednvx179r1urqdkolxfwi5xncfb5u6ib.png)
![Swim = 10km](https://img.qammunity.org/2022/formulas/mathematics/college/fxprug4w8gk5balsyzann93v1gb35tj0wv.png)
Required
Determine the total distance travelled
First, we need to calculate the fraction of the distance where the duck swim, using the following equation:
![Swim + Fly + Walk = 1](https://img.qammunity.org/2022/formulas/mathematics/college/vysa49cxps3xwkypxznad51x1h099te8nl.png)
![Swim + (3)/(4) + (1)/(9)= 1](https://img.qammunity.org/2022/formulas/mathematics/college/ntwtl4s7ivq4hrtzmlgerunlrqh9rpxb8q.png)
Collect Like Terms
![Swim = 1 - (3)/(4) - (1)/(9)](https://img.qammunity.org/2022/formulas/mathematics/college/ijvqbrln5dngwegu83adipikxouq8e599o.png)
Take L.C.M
![Swim = (36 - 27 - 4)/(36)](https://img.qammunity.org/2022/formulas/mathematics/college/uwv6mqs4proi47trbwx8sw11qfioxymutt.png)
![Swim = (5)/(36)](https://img.qammunity.org/2022/formulas/mathematics/college/y1ajcxzg6898oh816j8yw3kmbj3zfvmy95.png)
This means that the duck swim 5/36 of the journey.
So, we have:
![(5)/(36) * Total = 10km](https://img.qammunity.org/2022/formulas/mathematics/college/qh301yuxi1hkwil9usieqvn1wur3vy89gw.png)
Multiply through by
![(36)/(5)](https://img.qammunity.org/2022/formulas/mathematics/college/2cgerpg48n2djx5ilfod3nmjxyrnibb45a.png)
![(36)/(5)* (5)/(36) * Total = 10km * (36)/(5)](https://img.qammunity.org/2022/formulas/mathematics/college/4lg6if2pwsebw5lf22lmdjkf43sckavzv4.png)
![Total = 10km * (36)/(5)](https://img.qammunity.org/2022/formulas/mathematics/college/ygyfh3d8i5clqfiktm5ojqdimbxop7u5yd.png)
![Total = (360km)/(5)](https://img.qammunity.org/2022/formulas/mathematics/college/1zac17a95v3d2auysdzepdqfefrg8of0sf.png)
![Total = 72\ km](https://img.qammunity.org/2022/formulas/mathematics/college/v7c39svypj6iw2trpgt773kytbz7xwetb9.png)
Hence, the duck travelled 72km