Average (mean) = (sum of all the data) / (# of data)
sum of all the data = (average)(# of data)
Thus for 100 students with an average of 93,
sum of all data = (93)(100) = 9300
and for 300 students with an average of 75,
sum of all data = (75)(300) = 22500
Therefore you would expect the overall average to be
(9300 + 22500) / (100 + 300) = 79.5 %
Now if there are x # of advanced students and y # of regular students, then
x + y = 90 (total # of students) and 93x + 75y = 87(x + y) (overall average)
The second equation can be simplified to x - 2y = 0
Subtracting the two equations yields
x = 60 and y = 90
Therefore you would need 60 advanced and 30 regular students.
Answer:
She has $20 + $0.50n in her tip jar.
Step-by-step explanation:
Amount in tip jar at noon = $20
Average amount made from each customer = $0.50
Number of additional customers served after noon = n
Therefore, we have:
Additional amount made after noon = Average amount made from each customer * Number of additional customers served after noon = $0.50 * n = $0.50n
Amount in tip jar = Amount in tip jar at noon + Additional amount made after noon = $20 + $0.50n
Therefore, she has $20 + $0.50n in her tip jar.
Answer:
1.5x = 7.5 (a)
Step-by-step explanation:
If Billy has $7.50 remaining, then he can buy x no. of boxes.
Each box costs $1.50
So, 1.5x = 7.5
Properties of Logs
logb(x/y) = log<span>bx</span> - log<span>by</span>.
therefore
log5 (4/7)= log5 (4)- log5 (7)
<span>Solve log 5 (4) and log 5 (7) with the base change of the logarithm</span>
<span>log 5 4 = log 4 / log 5 </span>
Use the calculator:
<span>
<span>log 5 4 =0.8613531161
</span></span>
log 5 7 = log 7 / log 5
<span>log 5 7 =1.2090619551</span>
<span>log5 (4/7)= log5
(4)- log5 (7)=-0.347708839</span>
