Let c and d be the number of cds and dvds respectively.
c+d=12
c=12-d
The we are told that:
2c+3d=31, using c found above in this equation gives you:
2(12-d)+3d=31
24-2d+3d=31
24+d=31
d=7
So Phillip bought 7 dvds.
check...
3*7+2(12-7)=31
21+2(5)=31
21+10=31
31=31
Answer:
See the attachment
Step-by-step explanation:
It is convenient to use a spreadsheet or graphing calculator for this.
The correct answer is C.
Because by looking at the diagram you can see that angles 7 and 8 are intersected
Well, if y is the notebook cost, well x+y=6.28, x+x+0.70=6.28, 2x=5.58, x=2.79.
The pencil box costs $2.79, while the notebook costs $3.49.