3/3-1/3= 2/3 of the glasses
40 mph would be 120 miles in 3 hours (120/40)
80 mph is 120 miles in 1.5 hours(120/80)
3 - 1.5 = 1.5, not 3 hrs
Change the speed to 20 mph( 1/2 the speed) to double the hours.
20 mph = 6 hours(120/20)
40 mph = 3 hrs(120/40)
6 - 3 = 3 hours difference
Answer:
B. 14 square feet
Step-by-step explanation:
just took the test
ANSWER: 32 five-dollar bills
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EXPLANATION:
Let x be number of $5 bills
Let y be number of $10 bills
Since we have total of 38 bills, we must have the sum of x and y be 38
x + y = 38 (I)
Since the total amount deposited is $220, we must have the sum of 5x and 10y be 220 (x and y are just the "number of" their respective bills, so we multiply them by their value to get the total value):
5x + 10y = 220 (II)
System of equations:

Divide both sides of equation (II) by 5 so our numbers become smaller

Rearrange (I) to solve for y so that we can substitute into (II)

Substituting this into equation (II) for the y:

We have 32 five-dollar bills
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If we want to finish off the question, use y = 38 - x to figure out number of $10 bills

32 five-dollar bills and 6 ten-dollar bills