Problem 9. (12 points)

Andrey lives near the market, and during the summer holidays, he often helped one of the traders lay out fruits on the counter early in the morning. For this, the trader provided Andrey with a $10 \%$ discount on his favorite apples. But autumn came, and the price of apples increased by $10 \%$. Despite the fact that Andrey started school and stopped helping the trader, the $10 \%$ discount for him remained. What will Andrey's monthly expenses on apples be now, considering that he buys 2 kilograms monthly? Before the price increase, apples at the market cost 50 rubles per kg for all customers. (Provide the answer as a whole number, without spaces or units of measurement.)

#
# Answer: 99.

## Comment

Solution: the new price of apples at the market is 55 rubles per kg, with a discount of $10 \%$ applied to this price. Thus, the price for 1 kg for Andrei will be 49.5 rubles, and for 2 kg Andrei will pay 99 rubles monthly.