Random digit dialing<span> (RDD) is a method for selecting people for involvement in telephone statistical surveys by generating telephone numbers at </span>random<span>. </span>Random digit dialing<span> has the advantage that it includes unlisted numbers that would be missed if the numbers were selected from a phone book.</span>
Answer:
72
Step-by-step explanation:
<em>Since the ratio of blue jays to robin's was 6 to 7 then if there were 84 robins how many blue jays were there.</em>
<em>6 to 7 can also be express as 6/7</em>
<em>Thus, we can set up a proportion</em>
<em>6/7 = x/84</em>
<em>Now, we have to solve for x</em>
<em>x = 72</em>
<em>Hence, if there were 84 robin there would be 72 blue jays.</em>
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<u><em>~lenvy~</em></u>
Answer:
48
Step-by-step explanation:
Answer:
Step-by-step explanation:
Given the simultaneous equation 2p - 3q = 4 and 3p + 2q = 9, to get the value of p and q we will use elimination method.
2p - 3q = 4 ...................... 1 * 3
3p + 2q = 9 ..................... 2 * 2
Multiplying equation 1 by 3 and 3 by 2:
6p - 9q = 12
6p + 4q = 18
Subtracting both equation
-9q-4q = 12-18
-13q = -6
q = -6/-13
q = 6/13
Substituting q = 6/13 into equation 2
2p - 3(6/13) = 4
2p - 18/13 = 4
2p = 4+18/13
2p = (52+18)/13
2p = 70/13
p = 70/26
p = 35/13
<em>Hence p = 35/13 and q = 6/13</em>
<em></em>
<em>b) </em>If if 223ₓ = 87 find x
Using the number base system and converting 223ₓ to base 2 will give us;
223ₓ = 2*x² + 2*x¹ + 3*x⁰
223ₓ = 2x²+2x+3
Substituting back into the equation, 2x²+2x+3 = 87
2x²+2x+3-87 = 0
2x²+2x-84 = 0
x²+x-42 = 0
On factorizing:
(x²+6x)-(7x-42) = 0
x(x+6)-7(x+6) = 0
(x+6)(x-7) = 0
x+6 = 0 and x-7 = 0
x = -6 and 7
<em>Hence the value of x is 7 (neglecting the negative value)</em>
