Atrain travels 68 km at an average speed of 51 km/h. it then travels another 20 km at an average speed of 40 km/h before reaching its destination. calculate the average speed for the whole journey. also give the solution of this problem.

Without any equipment, you can see stars that are 2{,}800{,}0002,800,0002, comma, 800, comma, 000 light-years away. by looking through a small telescope, you can see stars that are 3{,}112{,}000{,}0003,112,000,0003, comma, 112, comma, 000, comma, 000 light-years away. approximately how many times as far can you see using a small telescope as without any equipment?