Question 8 8. Ray is making face masks and needs to
purchase elastic cord. He needs 10.25 cm
elastic cord for each face mask. He orders 20
m of elastic cord. If he doesn't want any of
the cord to be wasted, what is the least
amount of extra cord that he would need to
add to his order of 20 m?
A.
B.
9 cm
10.25 cm
C.
D.
20.09 m
20.9 m

9514 1404 393

  B.  9 cm

Step-by-step explanation:

The number of face masks Ray can make with 20 m of cord is ...

  (20 m)(100 cm/m)/(10.25 cm/mask) = 195.12195 masks

To make one more mask, he will need to buy an additional amount of ...

  (196 -195.12195)×(10.25 cm) ≈ 9.00 cm

Ray would need to add 9 cm of cord to his order.

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204

combine all like terms then its just a 2 step equation