Enea and his friends, less than ten people in total, go to a restaurant with a fixed price menu: the price for a second course of meat is €11 while for a second course of fish €13. If Enea and his friends spent €107 on second courses, how many second courses of fish did they order?

5

2

9

4

7

the answer is 4.

Worked gold has 75% gold while the remaining part is made up of some metals which allow it to increase its rigidity and vary its colour. Tommaso’s jewelry is famous for green gold rings made with 12.5% copper and 12.5% silver. If Thomas has 12 g of silver, 28 g of copper and 60 g of gold in stock, how many grams of green gold can he make at most?

74

96

72

80

88

correct answer is 80grams

is there a time effective way to solve these questions?