Answer/Step-by-step Explanation:
Given:
a = no. of DVDs
b = no. of CDs
Total cost ($) for DVDs and CDs = 
a. The cost for 1 DVD = 2.5(a) = 2.5(1) = $2.5
The cost for 1 CD = 2(b) = 2(1) = $2
b. Total cost for 4 DVDs and 4 CDs:
Substitute a = 4, and b = 4 into the equation.


Total cost for 4 DVDs and 4 CDs = $18
c. To find out if $20 would be enough to buy 6 DVDs and 3 CDs, substitute a = 6, and b = 3 into the equation. Solve for the total cost to see if it equals $20 or is less than $20. If it's greater than $20, then it won't be enough.


6 DVDs and 3 CDs cost more than $20, therefore, $20 is not enough.
Answer:
5 Number of rows 3 number of columns 7
6 number of rows 3 number of columns 26
Step-by-step explanation:
Answer:
Step-by-step explanation:
Original 873 New 781
The new went down by about 10.5%
873*10.5%= 91.67
873-91.67= 781.33
It decreased 10.5%
Answer:
22.1 grams
Step-by-step explanation:
At the end of each minute, (1 -17.1%) = 82.9% of the element remains. At the end of 19 minutes, the quantity has been multiplied by that value 19 times, so the remaining amount is ...
(780 g)(0.829^19) ≈ 22.1 g
After 19 minutes 22.1 grams remain.