If one pound of cement cost r dollars, what is the price of z pounds in cents

100rz cents.

Step-by-step explanation:

The price of cement with respect to its weight is proportional.

So, we can write p ∝ w  

where p is the price in dollars and w is the weight of the cement in pounds.

⇒ p = kw   (1) {Where, k = proportionality constant}

Given that, one pound of cement cost r dollars.

So, from equation (1), we can write

r = k(1)

⇒ k = r

So, the equation becomes p = rw (2)

Now, for w = z pounds, the price will be p = rz dollars. {From equation (2)}

Therefore, the price of z pounds in cents will be 100rz cents. (Answer)

Step-by-step explanation:

Given the system of equations:

Multiply the first equation by -2 and the second equation by 5, then add both equations to solve for :

Substitute into any equation to solve for :

Therefore, the solution to this system of equations is