The table shows the battery life of four different mobile phones: Mobile Phone Battery Life Phone
Battery Life (hours)
A 20
B 25
C 10
D 18
If 8.45% of the battery life of each mobile phone is used in a day by a typical user, which mobile phone would use a total of 1.69 hours of battery life in a day?
Phone A
Phone B
Phone C
Phone D

Using quick mental math, we can do 8% of 10 to get 0.8, which is close to the value of 0.0845*10. Also fairly quick is moving the decimal point over 1 spot to the right and we go from 0.0845 to 0.845 and that rounds to 0.8 when rounding to one decimal place. Recall that 8.45% = (8.45/100) = 0.0845

If you want to compute out the four results with a calculator, then it would look like this:

0.0845*20 = 1.69

0.0845*25 = 2.1125

0.0845*10 = 0.845

0.0845*18 = 1.521

and this shows that no other result (but choice C) is close to 0.8

So that's why the answer is choice C

Step-by-step explanation:

answer: the price of one pound cabbage = $ 0.8

the point (10,8) represents that the cost of 10 pounds cabbage is $ 8

step-by-step explanation:

since, here is a proportional relation between the number of pounds of cabbage (x) and the price in dollars (y).

therefore, we can write,

⇒ y = k x

where k is the constant of proportionality.

now, point (5,4) is in the line.

thus, it will satisfies the above equation of line.

⇒ 4 = 5 k

⇒ k = 0.8

thus, the equation of the line is,

y = 0.8 x

a) for x = 1,

y = 0.8

therefore, the cost of one pound of cabbage is 0.8 dollars.

b) in the below graph (10,8) represents that the cost of 10 pounds of cabbage is 8 dollars.