Question

Plz answer the questions in attachment...

both 11 and 12​

Answer 1

here is ur answer buddy.,

C.I. c f. actual f
0-10. 3. 3
10-20. 12-3. 9
20-30. 27-12. 15
30-40. 57-27. 30
40-50. 75-57. 18
50-60. 80-75. 5

hence the modar class=30-40
becoz the frequency in this class is highest I.e .,30

ii)
(x-√2)²-2(x+1)=0

x²+2-2√2x-2x-2=0
x²-2√2x-2x=0

x²-2(√2-1)x=0

condition for having two distinct real roots.....
D=b²-4ac>0
D=4(√2-1)²-4(1)(0)
D=4(2+1-2√2)
D=12-8√2>0

hope it helps.,