:> The following table shows the results when
from a recent survey in which 1500 teens were asked about the most
important inventions of the 20th century. Complete the missing
information.

#Personal computer:-

Percent

#Pacemaker:-

#Wireless communication:-

#Television:-

Percent

#Others

Check out the filled out diagram below.

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Explanation:

To get the percentage, we divide the actual number by the total surveyed. This produces the decimal form of the percentage. Don't forget to move the decimal point 2 spots to the right to convert to the percentage.

For the first row, we have 480 people out of 1500 who said the personal computer was the most important invention.

So, 480/1500 = 0.32 = 32% of the people surveyed say the personal computer was the most important invention.

The fourth row will be handled the same way:

150/1500 = 0.10 = 10%

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To go from a percentage to the actual number, we'll multiply the decimal form of the percentage by the number surveyed.

26% chose pacemaker, so 0.26*1500 = 390 people chose this item. Notice that 390/1500 = 0.26 = 26%

For the the third row, we have 0.18*1500 = 270 people who chose wireless communication as the most important.

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To deal with the last row labeled "other", you'll need to keep in mind that percentages always add up to 100% as that's the highest it can go in many practical situations.

The percentages we calculated so far were: 32%, 26%, 18%, 10%

Those percentages add to: 32%+26%+18%+10% = 86%

The missing item must be 14% since 100% - 86% = 14%

Therefore, 14% of the 1500 people surveyed picked "other".

14% of 1500 = 0.14*1500 = 210 will go in the "actual number" column for this bottom row. Notice that 210/1500 = 0.14 = 14%

Also, notice that all the values in the "actual number" column add up to 1500

480+390+270+150+210 = 1500

This helps confirm our answers.

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.