81- answer is ok but im not suree
Answer:
it may be A log x ........
Answer:
I should use at least 304 students
Step-by-step explanation:
Margin error (E) = t × sd/√n
E = 40
sd = 300
confidence level (C) = 98% = 0.98
significance level = 1 - C = 1 - 0.98 = 0.02 = 2%
t-value corresponding to 2% significance level and infinity degree of freedom is 2.326
n = (t×sd/E)^2 = (2.326×300/40)^2 = 17.445^2 = 304 (to the nearest integer)
100 notes were altogether
<em><u>Solution:</u></em>
Given that ratio of the number of $2 notes to the number of $5 notes was 4 : 1
number of $2 notes : number of $5 notes = 4 : 1
Let 4x be the number of $ 2 notes
Let 1x be the number of $ 5 notes
Given that total value of notes is $ 260
Therefore,
$ 2 (number of $ 2 notes ) + $ 5(number of $ 5 notes ) = $ 260
$ 2(4x) + $ 5(1x) = $ 260
8x + 5x = 260
13x = 260
x = 20
<em><u>Thus number of notes altogether is given as:</u></em>
4x + 1x = 4(20) + 1(20) = 80 + 20 = 100
Thus 100 notes were altogether
