Answer:
Cost for each:
box of cards=$12.95
stamp=0.44
The number of quantity for each:
box of cards=1
stamp=16
Now the equation should be as follow:
quantity(box of cards)+quantity(stamp)
1($12.95)+16($0.44)
$12.95+$7.04
$19.99
The total cost is $19.99 or simply 19 dollars and 99 cents
Step-by-step explanation:
19x - 11 = 10x + 7
9x = 18
x = 2
19x - 11 = 19(2) - 11 = 27
3y + 27 = 180
3y = 153
y = 51
answer
x = 2 and y = 51
Answer: 8 
hours
Step-by-step explanation:
Let x represent the time it takes if both are used.
The unit time it takes to fill the pool using the first house is 1/20 and also the unit time it takes to fill the pool using the second house is 1/16 , therefore:
1/16 + 1/20 = 1/x
= 
=
Therefore
x = 
Therefore, it takes 8 hours using both houses
Wavelength times frequency equals speed, so wavelength=1080/7000=0.154 feet.
