Respuesta :
p + r = 2.50
r = p + 1
p + p + 1 = 2.50
2p + 1 = 2.50
2p = 2.50 - 1
2p = 1.50
p = 1.50/2
p = 0.75 <=== pencil cost 75 cents
r = p + 1
r = 0.75 + 1
r = 1.75 .....ruler cost 1.75
r = p + 1
p + p + 1 = 2.50
2p + 1 = 2.50
2p = 2.50 - 1
2p = 1.50
p = 1.50/2
p = 0.75 <=== pencil cost 75 cents
r = p + 1
r = 0.75 + 1
r = 1.75 .....ruler cost 1.75