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 =120
——. ——
d. c

Also , Dora can plant 18 flowers more per day than Charlie
How many flowers can Charlie plant per day ?