Answer:
The ratio of the number of mangoes in the $3 stack to those in the $6 stack is 1 : 2
Explanation:
Let the number of mangoes bought by the grocery store be n. Also let the number of mango sold for $3 in one stack be x and the number of mango sold for $6 in the second stack be y.
Therefore:
x + y = z (1)
Also, the mangoes was sold at break even price, that is the cost of the mango and the price it was sold for was the same. Therefore:
Cost of buying = Price it was sold for
The cost of the mango = 5z and the price it was sold for = 3x + 6y
3x + 6y = 5z (2)
Substituting z = x + y in equation 1
3x + 6y = 5(x + y)
3x + 6y = 5x + 5y
6y - 5y = 5x - 3x
y = 2x
x / y = 1/ 2 = 1 : 2
The ratio of the number of mangoes in the $3 stack to those in the $6 stack is 1 : 2