Question

To hire a trailer the initial cost is $50 plus an additional charge of $10 per hour.
(a) Write an equation for the cost ($C) if you hire the trailer for t hours.

(b) What is the cost if you hire the trailer for 4 hours?

(c) How many hours was the trailer hired for if the total charge was $125?

Answer 1

a) An equation for the cost ($C) if we hire the trailer for t hours is the following:

$C(t)=50+10t$

b)  The cost if we hire the trailer for 4 hours is $C(4)=50+10\cdot4=50+40=90$

c) If the total charge was $125, then for hours $t$ we have the following equation:

$125=50+10t$

which is equivalent to

$10t=125-50$

and to

$10t=75$.

And consequently, t = 7.5 hours. Therefore, the trailer was hired 7 hours and 30 minutes.