Quiz 2 answer key
Math 1030-005 (Fall 2014)
1. You’d like to carpet a room that measures 18 feet by 15 feet. How many square yards of carpet
do you need? (3 points)
1 yard = 3 feet; 1 square yards = 9 square feet; 1 square feet = 1/9 square yards.
18 feet × 15 feet = 18 × 15 (feet × feet) = 270 (feet2 ) = 270 (1/9 yard2 ) = 270/9 (yard2 )
= 30 (yard2 ).
2. Convert 15◦ C to Fahrenheit degrees. (3 points)
Method 1: 15 degree Celsius is 15◦ C more than the freezing point (which is 0◦ C = 32◦ F ). When
◦
Celsius change by 1, Fahrenheit change by 9/5. this means it is 15 × 59 F = 27◦ F more than the
freezing point, so it is 32◦ F + 27◦ F = 59◦ F .
Method 2: Use the formula F = 1.8C+32. You plug in C = 15, to get F = 1.8×15+32, which is 59.
3. Convert 6◦ F to Celsius degrees. (3 points)
Method 1: 6 degree Fahrenheit is 26◦ F less than the freezing point (which is 0◦ C = 32◦ F ). When
◦
Fahrenheit change by 1, Fahrenheit change by 5/9. this means it is 26 × 95 F = 130/9◦ C less than
◦
the freezing point, so it is −130
= −14 49 C ≈ −14◦ C.
9
Method 2: Use the formula C =
◦
which is −130
= −14 49 C.
9
F −32
1.8
=
5
9
× (F − 32). You plug in F = 6, to get F =
5
9
× (−26),
4. Tom is traveling in Paris, and he purchases a 780c.c. bottle of orange juice, and it costs him 1
Euro. And he remembered the orange juice he had in his hometown was a 60 oz. bottle, which costed
him 3 US dollars. Which one is cheaper (lower price for the same amount)? (1 oz. = 28 c.c.; 1 Euro
= 1.3 US dollar) (Correct guess: 1.5 points; Calculations: another 1.5 points)
The 780c.c. bottle costs Tom 1 Euro, and 1 Euro means 1.3 USD, so we have 780c.c. = 1.3 USD
c.c. = 600c.c. = 1 USD in Europe.
in Europe. Divide both sides by 1.3, we get 780
1.3
In his hometown, 60 oz. = 3 USD. We know 1 oz. equals 28c.c., so 60 oz. means 60×28 = 1680c.c..
So we have 1680c.c. = 3 USD. Divide both sides by 3, we know that 1680
c.c. = 580c.c. = 1 USD.
3
Therefore, for each 1 USD spent, Tom gets more orange juice in Europe. This means the orange
juice in Europe is cheaper.