Предмет: Математика, автор: nadezhda0710198

в альбоме 1105 марок , число иностранных марок составило 30% от числа российских марок . сколько иностранных  и сколько российских марок было в альбоме? 

Ответы

Автор ответа: Trover
0
Российских марок x, иностранных x*30% = x*30/100 = 0,3x, всего x+0,3x = 1,3x или 1105 марок.
1,3x = 1105
x = 1105:13 = 850 - российских марок
1105-850 = 255 - иностранных марок.
Или
850*30/100 = 255 - иностранных марок.
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