Answer:
Each envelope is $1.42
Step-by-step explanation:
Let, the cost of postcards = x and the cost of envelopes = y, in dollars.
It is given that,
First customer paid $12 for 14 postcards and 5 envelopes.
This gives, 14x + 5y = 12.
Second customer paid $24.8 for 10 postcards and 15 envelopes.
This gives, 10x + 15y = 24.8
We get the system of equations,
14x + 5y = 12
10x + 15y = 24.8
We multiply 1st equation by 3. This gives us the equations,
42x + 15y = 36
10x + 15y = 24.8
Subtracting both equations, we get,
32x = 11.2
i.e. 
i.e. x = 0.35
Which gives,
10 × 0.35 + 15y = 24.8
i.e. 15y = 24.8 - 3.5
i.e. 15y = 21.3
i.e. 
i.e. y = 1.42
Hence, the cost of each postcard is $0.35 and each envelope is $1.42.
Answer:
If you write a number as a fraction, that number's reciprocal is a fraction with the numerator and the denominator switched around. For example, the reciprocal of
4
5
is
5
4
. Some general rules to keep in mind:
-If the fraction has a
0
in the numerator, the reciprocal is undefined.
-If the fraction has a
0
in the denominator, the fraction itself is undefined. Thus it can't have a reciprocal.
-Any other fraction has exactly one reciprocal.
Finally, the reciprocal of a reciprocal is the original fraction. This means if you flip a fraction's numerator and denominator, and then flip them back, you get the number you started with.
Step-by-step explanation:
Answer:
25.85
Step-by-step explanation:
The area of a circle is given by A = π * r²
We have the value of the area, so we clear r:
r² = A / π
r² = 2100 / π = 668.45
r = √668.45 = 25.85
Answer:
4.2
Step-by-step explanation:
Divide the mass value (384 oz) by 16
16 oz = 1 lb
384 divided by 16= 24
