Travis has hired Charlie and Dora to plant flowers. Dora can plant 150 flowers in the same time it takes Charlie to plant 120 flowers, which can be shown using the following relationship where d and c are the respective rates at which Dora and Charlie can plant flowers:
150 over d equals 120 over c
Also, Dora can plant 18 flowers more per day than Charlie.
How many flowers can Charlie plant per day?