Answer:
The first one
Step-by-step explanation:
304,913
The vertex and the t-intercept where t>0, will help solve this problem. Sending the work on the attachment.
Answer: 14
Step-by-step explanation:
Given
Excavation cone measures
height 
Diameter 
Truck can dump
at a time
The volume of a cone is

Putting values

No of trips(N) required to accumulate this much volume is given by

Therefore, 14 trips are necessary to accumulate a cone of volume 
Answer:
73
Step-by-step explanation:
x/5+7=16
times 5 both sides
x + 7 = 80
-7 -7
x=73