I hope I'm not wrong here, but B.1/2? Only because its a 50% chance
Let x and y represent the numbers of gallons used by the 40 mpg and 35 mpg cars, respectively.
.. x +y = 40 . . . . . . . . . . .total consumption is 40 gallons
.. 40x +35y = 1525 . . . . total miles driven = 1525
Multiply the first equation by 40 and subtract the second.
.. 40(x +y) -(40x +35y) = 40(40) -(1525)
.. 5y = 75
.. y = 15
.. x = 40 -15 = 25
The 40 mpg car consumed 25 gallons.
The 35 mpg car consumed 15 gallons.
You would set this up as Part÷Whole=Percent÷100
Part=117
Whole= X
Percent=78
117÷X=78÷100
Set these up as fractions and cross multiply. You will get 117×100=78X
117×100=11,700
Divide both sides by 78 and you get x=150
There were 150 problems
1. 3y
multiplying 3 and y together gets 3y
2. y-5
5 less implies that we subtract 5 from y
3. y+7
adding 7 to y, self-explanatory
4. 9y
same thing as #1
5. 
quotient of implies division, since number y is listed first, y is the numerator
