Answer:
Cost of shrubs = 23
Cost of tree = 47
Step-by-step explanation:
Let
Cost of shrubs = x
Cost of tree = y
13x + 4y = 487 (1)
6x + 2y = 232 (2)
Multiply (2) by 2
12x + 4y = 464 (3)
13x + 4y = 487 (1)
Subtract (3) from (1)
13x - 12x = 487 - 464
x = 23
Substitute x = 23 into (2)
6x + 2y = 232 (2)
6(23) + 2y = 232
138 + 2y = 232
2y = 232 - 138
2y = 94
y = 94/2
= 47
y = 47
Answer:
The minimum score required for an A grade is 88.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

Find the minimum score required for an A grade.
Top 12%, which is at least the 100-12 = 88th percentile, which is the value of X when Z has a pvalue of 0.88. So it is X when Z = 1.175.




Rounding to the nearest whole number
The minimum score required for an A grade is 88.