Given:
The first customer paid $17 for 7 small envelopes and 3 memo pads.
The second customer paid $28.75 for 12 small envelopes and 5 memo pads.
To find:
The cost in dollars of each memo pad.
Solution:
Let x be the cost of each small envelop and y be the cost of each memo pad.
The first customer paid $17 for 7 small envelopes and 3 memo pads.
...(i)
The second customer paid $28.75 for 12 small envelopes and 5 memo pads.
...(ii)
Multiply equation (i) by 12 and equation (ii) be 7 to get same coefficient of x.
...(iii)
...(iv)
Subtracting (iv) from (iii), we get
Therefore, the cost of each memo pad is $2.75.