My daughter needs help solving a math prblem , and she is in fourth grade. Can you assist us?
In a stationery stor, pencils have one price and pens have another price, Two pencils and three pens cost 78 cents. But three pencils and two pens cost 72 cents. How much does one pencil cost?
Pencil = p
Pen = P
2p + 3P = 78¢ call this eq1
3p + 2P = 72¢ call this eq2
multiply eq1 by (3) & eq2 by (-2)
6p + 9P = 234
-6p - 4P = - 144
then add algibrically
9P - 4P = 234 - 144
5P = 90
Pen (P) = 18
Subtitute P = 18 in eq1
2p + 3P = 78¢ call this eq1
2p + 3(18) = 78
2p = 78 - 3(18)
2p = 24
Pencil (p) = 12