Answer:
The value is
![D = 70.71 \ km](https://img.qammunity.org/2021/formulas/physics/college/1p1i2rn338u9sl2fjm063mudstql99mdyh.png)
Step-by-step explanation:
From the question we are told that
The speed of each train is
![v = 28 \ km/h](https://img.qammunity.org/2021/formulas/physics/college/8m291y7k5vwhrp1vpbt709q9dsu8uvwp8a.png)
The speed of the bird is
![v_1 = 60 \ km/h](https://img.qammunity.org/2021/formulas/physics/college/2xm7110i79hp2er81ytlmw1fpwawmoyd70.png)
The distance between the trains is
![d = 66 \ km](https://img.qammunity.org/2021/formulas/physics/college/inj4wwga4j4mvelwdo4ei9vppacdf8nru6.png)
Generally the time taken before the collision occurs is mathematically represented as
![t = (d)/(2 * v)](https://img.qammunity.org/2021/formulas/physics/college/wo93q9l08exzpcem66qsfkxle8h3ezq7jw.png)
=>
![t = (66 )/(2 * 28)](https://img.qammunity.org/2021/formulas/physics/college/q2ou6rgxr2kw6m8irrkneymixv1arsp9sn.png)
=>
The total distance covered by the bird is mathematically represented as
![D = v_1 * t](https://img.qammunity.org/2021/formulas/physics/college/dz75j379cxsaie772thur7mz6gr30bzmpo.png)
=>
![D = 60 * 1.18](https://img.qammunity.org/2021/formulas/physics/college/6fmca6vpmboqqzlwyezlw6fr87enj8gdhu.png)
=>
![D = 70.71 \ km](https://img.qammunity.org/2021/formulas/physics/college/1p1i2rn338u9sl2fjm063mudstql99mdyh.png)