Answer:
See joint picture.
Step-by-step explanation:
The study lasts 6 days. Since the amount of plant food decreased an equal amount each day, and since the whole 72 millimeters were used, it means that plants consumed 72/6 = 12 millimeters daily.
All the results given come from this justification.
Let, the number of bracelets be x and the number of necklaces be y.
Given, there are 120 pieces of jewellery which are bracelets and necklaces.
So we can write the equation, ....equation 1
Now given the price of bracelet = $7
So, the price of x bracelets = $ =$
Given, the price of necklace = $13.
So, the price of y necklaces = $ = $
The total amount for the jewellery given = $ 1080.
We can write the equation as,
....equation 2
Now from equation 1, we can write,
By substituting this value of x in equation 2, we will get,
Now we will move 840 to the right side by subtracting it from both sides. We will get,
We can get y by moving 6 to the other side by dividing it to both sides. We will get,
So we have got the number of necklaces = 40
Now we have,
So, the number of bracelets = 80
We have got the required answer here.