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**b_austintx** ok i have two questions that i need help on. ugh word problems...

1. a car tire has a small leak, and the tire pressure in pounds per square inch after t minutes is given by

P(t) = 32e (-0.2t) After how many minutes was the pressure 5 pounds per square inch?

*note the (-0.2t) is the exponent.

there is not time- so i'm not sure what to plug into (t)? plug in (60) for (t) since its talking about minutes?? and since its neg. i keep getting a neg. answer. but there is no such thing as a neg min. so i'm stuck....

2. Suppose $8000 is invested into a savings account that accrues intrest continuously at a rate of 2.3% determine how long it would take the investment to triple.

its continuously...there is no year or quartly so how do i solve?

i think the formula to use is

A=P (1 + r/t) ^ nt -----is this right?

what do i do for t? apparently time that i have the problem with in both questions.

can anyone help?