[Question] Drop rate how to count ?

Lets say EXP 1st , i saw a thread at [maplesea forum]
it write
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%Exp multiplier,
(i) pure grinding type: 100%
(ii)with elven blessing: 110%
(iii)with fairy pendant: 130%
(iv)with elven blessing and fairy pendant: 140%
(v) with HS alone: 150%
(vi) with HS and elven blessing: 165%
(vii) with HS, elven and pendant: 210%
(viii) with coupon alone: 120% ; 150% or 200%
(ix) with coupon, HS, elven blessing: 198% ; 247.5% ; 330%
(x) with coupon, HS, elven blessing and pendant: 252% ; 315% ; 420%
(xi) with coupon, HS, elven blessing, pendant and EXP potion (alchemy): 277.2% ; 346.5% ; 462%
(xii) with coupon, HS, elven blessing, pendant, EXP potion (alchemy) and server 2x: 554.4% ; 693% ; 924%! credits go to leonie
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lets an example ,
Merc Link Skill 10% + Fairy Pendants 30% + Base normal 100% = 140% < this is his answer
But With Buff = HS 50% = 140% * 50% = 210%

how it count ? , Char Eq & Link Skill is "+" , Buff is "x" ?



ok below , lets use the same formular , EXP Change To Drop Rate ##
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Self Eq
Base 100%
___Accessory Eq , 140%___
Pendants [20%]
Belt [20%]
Eyes [20%]
Face [20%]
Earring [20%]
Ring [10%] (have 4)
Total = 140%
2x Coupon 200%
Winter Lucky Buff [the xmas Coupon] 50%
Demon Slayer [Demon Cry] 20%
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Base + Accessory Eq = 100% + 140% = 240%
Base + Accessory Eq * Coupon = 240% * 2 = 480%
Base + Accessory Eq * Coupon * xmas Coupon = 480% * 50% = 720%
Base + Accessory Eq * Coupon * Demon Cry = 480% * 20% = 576%
Base + Accessory Eq * Coupon * xmas Coupon * Demon Cry = 720% * 20% = 846%
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my english not so good , hope u all know what i mean