Answer:
$ 1.10
Step-by-step explanation:
p + r = 1.45....p = 1.45 - r
2p + r = 1.80
2(1.45 - r) + r = 1.80
2.90 - 2r + r = 1.80
-2r + r = 1.80 - 2.90
-r = - 1.10
r = 1.10 <=== a ruler costs $ 1.10
p + r = 1.45
p + 1.10 = 1.45
p = 1.45 - 1.10
p = 0.35 .......a pencil will cost $ 0.35
