Step-by-step explanation:
(2c+c) + 12 =78
3c + 12 = 78
78 - 12 = 66
66 ÷ 3 = 22
22 + 22 + 22 + 12 = 78
{ C = 22 }
Answer:
3,266.53
Step-by-step explanation:
Answer:
- 
Step-by-step explanation:
=
( cross- multiply )
6x = 5y ( divide both sides by 6 )
x =
y
Then
← substitute x =
y into the expression
= 
= 
= 
=
× - 
= - 
<span>Answer:
Roma Sherry drove 330 miles from her hometown to Tucson. During her return trip, she was able to increase her speed by 11 mph. If her return trip took 1 hour less time, find her original speed and her speed returning home.
:
Let s = original speed
then
(s+11) = return speed
:
Write a time equation: Time = distance%2Fspeed
:
Original time = return time + 1 hr
330%2Fs = 330%2F%28%28s%2B11%29%29 + 1
:
Multiply equation by s(s+11) and you have:
330(s+11) = 330s + s(s+11)
:
330s + 3630 = 330s + s^2 + 11s
:
0 = 330s - 330s + s^2 + 11s - 3630
:
A quadratic equation:
s^2 + 11s - 3630 = 0
Factor this to:
(s + 66)(s - 55) = 0
Positive solution
s = 55 mph is original speed.
:
Find the time
330/55 = 6 hr, original time
and
330/66 = 5 hrs, faster time; confirms our solution.</span>