X=2 because 3 times 2 is 6 and then you add 6 and 7 together and get 13.
Answer:

Step-by-step explanation:
The given sequence is
-12,-16,-20...
The first term of this sequence is
.
The common difference is


The nth term of this arithmetic sequence is;

We substitute the values for the first term and the common difference to obtain;

Answer: She would need 206 paper cups.
Step-by-step explanation: First of all, Monica has a 10-gallon container full of lemonade and this translates into 37850 cubic centimetres volume of lemonade. The conversion rate has been provided as one gallon equals 3785 cubic centimetres, therefore ten gallons would be 3785 times ten which gives you 37,850 cubic centimetres of lemonade.
Each cone shaped paper cup has a diameter measuring 8 centimetres and 11 centimetres in height. The radius of the cone shaped cup therefore is 4 centimetres (radius equals diameter divided by two). The volume of each cup therefore is given as;
Volume of a cone = (πr²h)/3
Volume of a cone = (3.14 * 4² * 11)/3
Volume of a cone = 552.64/3
Volume of a cone = 184.2
If each cone could hold 184 cubic centimetres of lemonade, then the entire ten gallons would require the following number of cone shaped cups;
Number of cups = Total volume/Volume of a cup
Number of cups = 37850/184.2
Number of cups = 205.48
Rounded to the nearest whole number, this becomes
Number of cups ≈ 206
Therefore Monica would need 206 cone shaped paper cups to empty the entire 10 gallons of lemonade.
Dividing the number of tires that should be installed per day which is 400 by the number of working hours which is 8 will give us 50 tires per hour. Assuming that the same mistake will take toll on the workers such that they will have 1 tire mistakenly installed in an hour, they will have 8 erroneous tires in a day. Multiplying this by 5 to make the answer per week will give 40. Out of the 400 x 5 = 2000 tires. The answer would be 2000 - 40 which is equal to 1940. The assumption must be valid.