Предмет: Математика, автор: 5236987

18 ручек стоят на 30 рублей больше, чем 30 карандашей. Те же 18 ручек стоят на 10 рублей больше, чем 40 таких же карандашей. Сколько стоит один карандаше и одна ручка?

Ответы

Автор ответа: Alex1113
13
Пусть ручка стоит х рублей, а карандаш у рублей. Составляем систему уравнений
18х-30у=30
-18х-40у=10
-----------------
10у=20
у=2 рубля стоит карандаш
18х-30*2=30
18х=30+60
18х=90
х=5 рублей стоит ручка
Ответ: ручка стоит 5 рублей, карандаш стоит 2 рубля
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