3/5 is the answer! I hope this helps!
Answer: 720 ways
Step-by-step explanation:
Given
A train has 1 main engine and remaining 6 train cars
If the engine is always in the front the remaining train cars can be arranged is

The answer is 300.
Hope this helps!
Answer:
60°
please look into the solution down here.
Step-by-step explanation:
since BD bisects it, then the angles should be bisected symmetrically, or in other words, ANGLE ABD = angle DBC,
hence,
4x = 2x +30
2x = 30
x = 15
therefore, angle DBC = 2x + 30 = 2(15) + 30 = 60°.