about vann diagram

自己劃隻 vann diagram ,
易明 d, 呢度我唔識點劃比你睇
let m be no. of people who like F and G only
n be no. of people who like H and G only
p be no. of people who like H only
x be no. of people who like G only
120 = 50 + 20 + 28 + m, m = 22
160 = 28 + m + n + x, n + x = 110
100 = 20 + 28 + p + n, p + n = 52
280 = 50 + 20 + 28 + m + n + x + p + 15, n + x + p = 145
solving above eqt.s,
p = 35, n = 17, x = 93
93 people like G only

There are 8 regions: F, H, G, FH, FG, GH. FGH, none

Total F = F only + FH + FG + FGH
120 = 50 + 20 + FG + 28
FG = 22

Total H = H only + FH + GH + FGH
100 = H + 20 + GH + 28
H+ GH = 52 ... (1)

Total G = G only + FG + GH + FGH
160 = G + 22 + GH + 28
G + GH = 110 ... (2)

Total = F + H + G + FH + FG + GH + FGH
280 - 15 = 50 + H + G + 20 + 22 + GH + 28
H + G + GH = 145 ...(3)

From (1), H = 52 - GH
From (2), GH = 110 - G
Sub to (3), (52-GH) + G + (110 -G) = 145
162 - (110 - G) = 145
52 + G = 145
G = 93

So, liked product G only 93.