Question

В зоомагазине было 8 гуппи и 24 моллинезии Шура купил половину моллинезий и 3 гуппи за 81 рубыль а остальных рыбок купил Дима за 87 рублей. Сколько стоила каждая рубка. помогите пожалуйста решить задачу

Answer 1

12 моллинезий и 3 гуппи стоят 81 рубль
12 моллинезий и 5 гуппи стоят 87 рублей
судя по разнице в количестве гуппи на 2 шт больше
и разнице в цене на 6 руб дороже
можно сделать вывод, что 2 гуппи стоили 6 руб, т.е.
6:2=3(руб) одна гуппи
теперь считаем сколько стоят моллинезии
если Шура отдал 81 руб за 12 моллинезий и 3 гуппи, то
3*3=9(руб) стоят 3 гуппи
81-9=72(руб) стоят 12 моллинезий
72:12=6(руб) стоит одна моллинезия

ответ: гуппи 3 руб, моллинезия 6 руб.

Answer 2

To solve this problem, we need to determine the cost of each fish. Let's break down the information given:

- In the pet store, there were 8 guppies and 24 mollies. - Shura bought half of the mollies and 3 guppies for 81 rubles. - Dima bought the remaining fish for 87 rubles.

To find the cost of each fish, we can set up a system of equations. Let's denote the cost of a guppy as "g" and the cost of a molly as "m."

Setting up the equations:

1. Shura's purchase: - Cost of 3 guppies: 3g - Cost of half the mollies: (1/2) * 24m = 12m - Total cost: 3g + 12m = 81 rubles

2. Dima's purchase: - Cost of the remaining guppies: (8 - 3) * g = 5g - Cost of the remaining mollies: (24 - 12) * m = 12m - Total cost: 5g + 12m = 87 rubles

Solving the system of equations:

We can now solve the system of equations to find the values of "g" and "m."

From Shura's purchase: 3g + 12m = 81

From Dima's purchase: 5g + 12m = 87

To eliminate "m," we can subtract the first equation from the second equation:

(5g + 12m) - (3g + 12m) = 87 - 81 2g = 6 g = 3

Now that we have the value of "g," we can substitute it back into one of the equations to find the value of "m." Let's use the first equation:

3g + 12m = 81 3 * 3 + 12m = 81 9 + 12m = 81 12m = 81 - 9 12m = 72 m = 6

Solution:

Therefore, the cost of each guppy is 3 rubles, and the cost of each molly is 6 rubles.