A bank lobby has 7 lamps. Each lamp requires 3 light bulbs, and each bulb costs $0.79, including tax. What would be the cost of replacing all the light bulbs in the lobby?

16.59

Step-by-step explanation:

21 x .79

(7 x 3 = 21)

answer: options

step-by-step explanation:

this is a direct variation proportion. y = kx

y is the total amount due, k is the constant of variation, and x is the number of texts sent.

plug in the 3.20 and the 16 to solve for the "k". this is the constant of proportionality. it is the value that will not change.

3.20 = k(16). solving you get $.20 per text.

the equation would then be y = .20x