Question

The expression 2.5a+2b gives the cost (in dollars) for a DVDs and b CDs at a moving sale. a. The cost for 1 DVD is $ and the cost for 1 CD is $ . b. The total cost for 4 DVDs and 4 CDs is $ . Question 2 c. Is $20 enough to buy 6 DVDs and 3 CDs?

Answer 1

Answer/Step-by-step Explanation:

Given:

a = no. of DVDs

b = no. of CDs

Total cost ($) for DVDs and CDs =
`2.5a + 2b`

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.

`2.5(4) + 2(4)`

`10 + 8 = 18`

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.

`2.5(6) + 2(3)`

`15 + 6 = 21`

6 DVDs and 3 CDs cost more than $20, therefore, $20 is not enough.