Answer:

Step-by-step explanation:
Let
Side of square base=x
Height of rectangular box=y
Area of square base=Area of top=
Area of one side face=
Cost of bottom=$9 per square ft
Cost of top=$5 square ft
Cost of sides=$4 per square ft
Total cost=$204
Volume of rectangular box=
Total cost=



Substitute the values of y

Differentiate w.r.t x







It takes positive because side length cannot be negative.
Again differentiate w.r. t x

Substitute the value

Hence, the volume of box is maximum at x=2.2 ft
Substitute the value of x

Greatest volume of box=
You can either do;
1. 90(2) = 100(2)
180 = 200
In 3 minutes, they can write 200 words. So now we can divide by 3.
3/3 = 1 minute
200/3 ≈ 66.666
or
2. 90/3 = 30 secs
100/3 ≈ 33.333
30(2) = 1 minute
33.333(2) ≈ 66.666
Either way, the admin assistant can write 67 words per minute. (Rounded to the nearest whole)
Answer:
12 months
Step-by-step explanation:
Given that:
Mario:
12 stamps per month
Since January
Karen :
18 stamps per month
Starts on july
Number of stamps collected by Mario till the end of June :
12 * 6 = 72 stamps
For Mario :
72 + 12x
For karen:
18x
Where x is the number of months after karen starts :
Equate both equations
72 + 12x = 18x
72 = 18x - 12x
72 = 6x
x = 72/6
x = 12
After 12 months
Number of months after karen starts, will they have same amount of stamp
Answer: 24
Step-by-step explanation:
Sample mean=∑ fx ÷ n
mean=432 / 18
mean=24