nursery owner buys 8 panes of glass to fix some damage to her greenhouse the panes cost $20.40 unfortunately she breaks 3 more panes while repairing the damage what is the cost of another 3 panes?

The cost of another 3 panes of glass would be  

Solution:

Given, Number of panes of glass bought = 8

Cost of 8 panes of glass =  

Number of broken panes of glass = 3

We have to find the cost of 3 panes of glass

By unitary method, If 8 panes of glass costs , then the cost of one pane of glass will be as follows,

Therefore, for 3 panes of glass it would be  

Unitary method:

The unitary method is a technique for solving a problem by first finding the value of a single unit, and then finding the necessary value by multiplying the single unit value. In essence, this method is used to find the value of a unit from the value of a multiple, and hence the value of a multiple.