A contractor requires a cement mix that is 70% sand and 30% cement. He has 1400 kg of a cement mix that is 80% sand and 20% cement. How much cement should he add to this 1400 kg cement mix so that he gets the required mix?

added cement = 200 kg

Step-by-step explanation:

Sand = 0.8*1400

Sand = 1120 kg

If 1120 kg of sand represents the total sand in the 8:2 mixture.

We have to create the equation of the 7:3 mixture as follows.

The sand amount continues the same but the total amount of the mixture and cement will change.

0.7*mixture_mass + 0.3*mixture_mass = mixture_mass

By replacing values, we have:

1120 kg + 0.3*(1400 kg + added cement)= 1400 kg + added cement

added cement = 200kg

walter needs to make at least 5 more cookies but no more than 40. 5 ≥ x ≥ 40;

step-by-step explanation:

walter has to make a minimum of 20 cookies. he already has 15 cookies made, so he must make 5 more to meet the minimum.

the maximum amount of cookies he can make is 55. he already has 15, so he has to make no more than 40 more cookies to meet the maximum.

step-by-step explanation:

i found the koficent of the linear function and i foun c acordind to the strict formula y=kx+c and then i took 2 as an x and replacet it on the formula i found and then foun the y