You can choose between two telephone companies. Company A has a monthly charge of $10 plus 5¢ a minute for each minute of long distance calls. Company B has a monthly charge of $8 plus 6¢ a minute for long distance calls. How many minutes must you use to make Company A a better deal

Company A would be a better deal for number of minutes over 200

Step-by-step explanation:

Let x represent the number of minutes that you would use with either company A or company B.

Company A has a monthly charge of $10 plus 5¢ a minute for each minute of long distance calls. It means that the cost of x minutes of long distance call is

10 + 0.05x

Company B has a monthly charge of $8 plus 6¢ a minute for long distance calls. It means that the cost of x minutes of long distance call is 10 + 0.05x

8 + 0.06x

For Company A to be a better deal, it means that

10 + 0.05x < 8 + 0.06x

10 - 8 < 0.06x - 0.05x

2 < 0.01x

0.01x > 2

x > 2/0.01

x > 200

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.

the answer is two. hope this !