SOLUTION: A trucks varying distance from the warehouse,d,measured in miles is modeled by the formula d=t squared+ 70t where t is the varying number of hours since the truck left the warehou

Algebra ->  Finance -> SOLUTION: A trucks varying distance from the warehouse,d,measured in miles is modeled by the formula d=t squared+ 70t where t is the varying number of hours since the truck left the warehou      Log On


   

Question 1126108: A trucks varying distance from the warehouse,d,measured in miles is modeled by the formula d=t squared+ 70t where t is the varying number of hours since the truck left the warehouse. The trucks destination is 442.25 miles away.
A)how many hours will it take the truck to reach the destination?
B) a car left the warehouse at the same time as the truck and wants to get to the destination at the same time. What constant speed would the car have to travel in order to reach the destination at the same time as the truck?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+d+=+t%5E2+%2B+70t+
+d+=+442.25+
+t%5E2+%2B+70t+-+442.25+=+0+
+t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+a+=+1+
+b+=+70+
+c+=+-442.25+
+t+=+%28+-70+%2B-+sqrt%28+70%5E2+-+4%2A1%2A%28-442.25%29%29%29%2F%282%2A1%29+
+t+=+%28+-70+%2B-+sqrt%28+4900+%2B+1769+%29+%29%2F2+
+t+=+%28+-70+%2B-+sqrt%28+6669+%29+%29%2F2+
+t+=+%28+-70+%2B+81.664+%29%2F2+
+t+=+11.664%2F2+
+t+=+5.832+
(a)
5.832 hrs away
(b) +442.25+=+r%2A5.832+
+r+=+75.832+ mi/hr
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check my math