A store sells a basic model of a phone for $60 and the upgraded model for $200. It cost to store $10 to buy each basic model and $50 to buy each upgraded model from the phone company. On Tuesday, the store has $1800 in sales for these two models, and it paid the phone company $400 to buy these phones. How many upgraded models does the store sell on Tuesday? 6 upgraded phones, 10 upgraded phones, 15 upgraded phones, 42 upgraded phones?

6

upgraded phones were sold on Tuesday

Step-by-step explanation:

Here, we want to know the number of upgraded phones sold by the company on Tuesday;

From the question, we are told that the company made $1,800 in sales on Tuesday;

Let the number of basic phones sold be x while the number of upgraded ones sold be y

Revenue from the basic ones would be 60 * x = 60x

Revenue from the upgraded ones will be 200 * y = 200y

By adding both, we will have the total sales;

60x + 200y = 1800 •••••••(i)

Also we are given the amount that the company paid to get these phones;

Cost of basic = 10 , so cost of x basic = 10 * x = 10x

Cost of upgraded = 50, so cost of y upgraded = y * 50 = 50y

Adding both;

10x + 50y = 400 •••••(ii)

So we have two equations to solve;

From ii, 10x = 400-50y

we can rewrite equation 1 as follows;

6(10x) + 200y = 1800

Substitute 10x = 400-5y into equation ii

6(400-50y) + 200y = 1800

2400 -300y + 200y = 1800

2400 -100y = 1800

100y = 2400-1800

100y = 600

y = 600/100

y = 6

This means 6 upgraded phones were sold on Tuesday

b

step-by-step explanation: