The cost of making a dress is partly constant and partly varies with the amount of time it takes to make the dress. If the dress takes 3 hours to make, it cost #2700. If it takes 5 hours to make the dress, it cost #3100. Find the cost if it takes 1¹/² hours to make the dress.

Answer 1

Let x be the constant cost of making the dress and y be the cost per hour of making the dress.

From the given information, we can create a system of two equations:

3y + x = 2700
5y + x = 3100

Subtract the first equation from the second equation:

(5y + x) - (3y + x) = 3100 - 2700
2y = 400
y = 200

Now, substitute the value of y back into one of the equations to solve for x:

3(200) + x = 2700
600 + x = 2700
x = 2100

Therefore, the cost of making the dress if it takes 1¹/² hours to make is:

1.5(200) + 2100 = ₦3000