Answer:
272?
Step-by-step explanation:
10 x 8 = 80
12 x 16 = 192
192 + 80 = 272.
Not sure
Answer:
declaration = - 0.55 m/s²
Step-by-step explanation:
The declaration is a negative accelaration.
Therefore:

a = ?
v = 70 of 15% = 10.5 km/h to m/s = 2.9 m/s
u = 70 km/h to m/s = 19.4 m/s
t = 30 seconds

a = - 0.55 m/s²