Answer: b.14
Step-by-step explanation:
We have two shelves, the top shelf and the bottom shelf .
Now, firstly we are told the top shelf has 10 more than 1/3 the number of books on the bottom shelf. This can be expressed as:
(1)
Then, we are told there are 12 books on the bottom shelf:
(2)
Substituting (2) in (1):
(3)
(4)
(5) This is the number of books on the top shelf
Hence, the correct option is b.
Answer:
Surface area of prism=
Step-by-step explanation:
We are given that surface area of rectangular prism=
We have to write an expression that represents the surface area of prism.
Base of prism is made from length and width
Perimeter of base =2(l+w)
Area of base=lw=Area of top
Surface area of prism=Perimeter of base multiply by height+2 area of base
Because area of base and area of top are equal.
Surface area of prism=Ph+2B=2(l+w)h+2(lw)
<em>Answer:</em>
<em>n = 12</em>
<em>Step-by-step explanation:</em>
<em>85%×n = 10.2</em>
<em>85n/100 = 10.2</em>
<em>85n = 1020</em>
<em>n = 1020 : 85</em>
<em>n = 12</em>
Answer:
20% alcohol = 1 gal
10% alcohol = 9 gal
Step-by-step explanation:
Let
x = 20% alcohol
y = 10% alcohol
x + y = 10 (1)
0.20x + 0.10y = 10*0.11
0.20x + 0.10y = 1.1 (2)
From (1)
x = 10 - y
Substitute x = 10 - y into (2)
0.20x + 0.10y = 1.1
0.20(10 - y) + 0.10y = 1.1
2 - 0.20y + 0.10y = 1.1
- 0.20y + 0.10y = 1.1 - 2
-0.10y = -0.9
y = -0.9/-0.10
y = 9 gal
substitute y = 9 into (1)
x + y = 10
x + 9 = 10
x = 10 - 9
x = 1 gal
20% alcohol = 1 gal
10% alcohol = 9 gal
Call T the price of the T-shirts and P de price of the jeans
Initially (without discount)
2T + P = 40
One month later (half prices)
2 (T/2) + 5(P/2) = 60
T +5P/2 = 60
To solve the system of equations multiply the second equation by 2 and substract it from the first equation
2 T + 5P = 120
- (2 T + P = 40 )
________________
4P = 80
P = 80/4
P = 20
From 2T + P = 40
T = (40 - P) / 2 = (40 -20) / 2 = 20/2 = 10.
The price of a T-shirt is $10 and the price of a pair of jeans is $20.