Answer 1

Class-interval:	0 - 10	10 - 20	20 - 30	30 - 40	40 - 50	50 - 60	60 - 70	70 - 80
Frequency:	5	8	7	12	28	20	10	10

L = 40, h = 50 - 40 = 10, f = 28, f1 = 12 and f2 = 20

Mode `=L+(f-f_2)/(2f-f_1-f_2)xxh`

`=40+(28-12)/(2xx28-12-20)xx10`

`=40+(16xx10)/24`

`=40+160/24`

= 40 + 6.67

= 46.67