Question

A nursery owner buys 7 panes of glass to fix some damage to his greenhouse. The 7 panes cost $15.05, Unfortunately, he breaks 2 panes while repairing the damage. What is the cost of another 2 panes of glass?

Answer 1

`"Two panes of glass cost $4.30."`

Explanation:

You can find this answer by using logic.

First find the cost of one pane of glass (the "unit cost")

7 panes of glass cost `$15.05`, so one pane of glass costs

`15.05 -: 7`

`color(white)(nn)` `$2.15` `larr` cost of one pane of glass

Then use that answer to find the cost of two panes of glass

If one pane of glass costs `$2.15`, then `2` panes cost

`2 xx $2.15`

`color(white)(.)` `$4.30` `larr` cost of two panes of glass

Answer:
`"Two panes of glass cost $4.30."`