How to Find the mean, median and mode from the following data

Class Interval------ Frequency

20-29----------- 6

30-39----------- 15

40-49----------- 21

50-59----------- 29

60-69----------- 25

70-79----------- 22

80-89----------- 11

90-99----------- 9

100-109-------- 3

110-119-------- 1

120-129-------- 2