Screenshot below-mathematics ,help please!!

(a) range = difference between highest

mark and lowest mark

range of marks = 10 - 6

= 4

(b) total students = marks × frequency

(6×5)+(7×4)+(8×7)+(9×10)+(10×4)

= 30+28+56+90+40

= 244 students

(c) total frequency = 5+4+7+10+4

= 30

mean mark = total students/total

frequency

= 244/30

= 8.133

i found two solutions,   n = 2 • ± √3 = ± 3.4641

step-by-step explanation:

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons