Question

answer the above question.​

Answer 1

Step-by-step explanation:

Here's your answer!!!

Refer to the above picture mate..

Answer 2

Answer:

f1 is 20 and f2 is also 20

Step-by-step explanation:

make separate columns for class mark(x) and fx

x fx

20 1800

40 40f1

60 1800

80 80f2

100 4000

√fx= 7600+ 40f1+ 80f2

√f= 160+ f1+f2

mean=√fx/√f

50= 7600+40f1+80f2/160+f1+f2

8000+50f1+50f2= 7600+40f1+80f2

400= -10f1+30f2

3f2-f1= 40---------1⃣

also 160+f1+f2= 200

f2+f1= 40----------2⃣

equate 1⃣ and 2⃣ by elimination method.

you'll get f2= 20 and f1= 20

hope it helped :)