Who is asking: Student
Nicole has 25 CDs and tapes altogether. When she tries to pair them up, she has 4 CDs left over. How many tapes does Nicole have?
Imagine that she is trying to stack the tapes and CD's side by side.
||If Nicole had 12 tapes then she would have 13 CD's and the CD pile would be 1 higher than the tapes pile.
||If Nicole had 11 tapes then she would have 14 CD's and the CD pile would be 3 higher than the tapes pile.
||If Nicole had 10 tapes then she would have 15 CD's and the CD pile would be 5 higher than the tapes pile.
She doesn't seem able to have 4 more CD's than tapes.
Try it algebrically. Let C be the number of CD's she has and T the number of tapes she has. What we know is
C + T = 25
C - T = 4
If you add these equation you get
2C = 29
C = 14 1/2
But C has to be an integer and hence what Nicole describes is impossible.
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