Suppose s and h are the mileage numbers for the SUV and Hybrid, respectively. Then if each vehicle drives 1 mile, the total gas consumption is
.. 1/s +1/h
Then the combined mileage is
.. 2/(1/s +1/h) = 2sh/(s+h)
Option 1: s=12, h=60
.. mpg = 2*12*60/(12+60) = 20
Option 2: s=11, h=75
.. mpg = 2*11*75/(11 +75) = 1650/86 ≈ 19.2
In summary,
.. Option 1: 20.0 mpg
.. Option 2: 19.2 mpg
_____
It usually works out best to increase the efficiency of the least-efficient contributor, as here.
This should help you out!
You turn the decimal into a percent
First let us calculate the total cost before tax:
1.06 * cost = 16.43
cost = 15.5
Therefore the cost of sunscreen is:
2 * Sunscreen + 6.50 = 15.5
2 * Sunscreen = 9
Sunscreen = $4.50
<span>Hence each bottle of sunscreen cost $4.50</span>
