The tens digit of a two-digit number is twice the units digits. If the digits are reversed, the new number is 18 less than the original number. Find the number.

x=42

Step-by-step explanation:

The tens digit of a two-digit number is twice the units digits. put it in an equation:

10(2x)+x = 10x+2x+18

21x=12x+18

21x-12x=18

x=18/9=2

substitute x:

10(2x)+x = 10x+2x+18

10(2*2)+2=10(2)+2(2)+18

42=24+18

it costs $20 to interview each person for a survey. find the cost to obtain a +- 3% margin of error.

step-by-step explanation:

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